With the booming development of blockchain technology, the application of blockchain technology has been extended to many fields, such as digital finance, Internet of Things, intelligent manufacturing, management of supply chain, digital asset trading and so on. The number of global patent applications is increasing year by year in order to gain a competitive position in technology and market. Taking the Derwent innovation platform as the data source, and with the help of Excel, DDA (Derwent data analyzer), DI (Derwent innovation) and Incopat as the data processing tools, this paper makes a global and domestic application situation analysis of patents in the field of blockchain technology, and further excavates and analyzes the core technologies, high-value patents and key research institutions in the field of blockchain technology. The results show that the global patent application in the field of blockchain technology is developing rapidly, and the distribution of countries/regions continues to expand. China is the main source country and market country of technology in this field, and its key institutions mainly distribute patents in the domestic market. However, the highly cited patents are generally from the United States, and its key institutions have a wide distribution around the world, indicating that the United States has strong strength in the core technology. Through the analysis of the core technology in the field of blockchain, it is found that patents mainly focusing on the digital information processing and transmission technology. The hot fields include identity authentication, smart contract, public and private keys and hash algorithm. The highly cited patents mostly involve validation and recordation of virtual asset transactions, authentication and verification of digital data and digital signatures, etc. China should pay attention to the research and development of the underlying technology, and actively grasp the layout of hot technology, so as to build China’s core competitiveness in this field. 

Under the dual pressure of the economic crisis and technological change, major changes have taken place in the global monetary and financial system. This paper uses bibliometrics to analyze the topics of digital currency based on blockchain technology aiming to grasp the current situation and research content of digital currency. The results show that digital currency research is in a rapid development stage and the regional characteristics are obvious. The security and privacy of digital currency, blockchain technology consensus algorithms, the energy consumption of the blockchain in the mining process, transactions security based on Ethernet and smart contracts, financial supervision of digital currencies, and machine learning are the main research contents of blockchain technology in the application of digital currency. In the future, blockchain technology will face severe challenges, including the research of encryption technology, the security of smart contracts, consensus mechanisms, scalability, and financial supervision. This article is expected to provide guidance and suggestions for the future development and policy formulation of blockchain technology in the digital economy.

As an important force leading the development of the global blockchain, U.S.'s practices is worth discussing and using for reference in promoting the development of the blockchain. This article analyzes relevant U.S. initiatives from the perspectives of R&D, supervision, standards, etc.. It is found that the U.S. Office of Science and Technology Policy has not made blockchain development a priority, but the government’s support for blockchain has been extended to many fields; the development of the U.S. Congress has changed from laissez-faire to the establishment of a clear regulatory system, and the states have become more active in the supervision of blockchain; mastering the international initiative and solving the industry standard problems is the main approach to the construction of blockchain standard system. It is claimed that the current prospect of the integration of blockchain and non-financial fields has emerged. Chinese government should increase its support for key blockchain technology and application research, improve the definition and classification of digital assets, establish a blockchain testing and certification standardization national laboratory, avoid improper constraints on technology and industrial development, and set up an extensive blockchain evaluation system.

With the continuous expansion of application fields, blockchain technology has received extensive attention from the whole society. This paper uses the Herfindahl-Hirschman index and the entropy index to measure and analyze the patent concentration of China's blockchain technology patent holders, various branches, and provinces. The results show that China's blockchain technology patents are generally decentralized, but the concentration degrees of patents in the branches of blockchain technology are significantly different. Among them, the patents of data layer and application layer technologies are more scattered, and the patents of incentive layer technologies are more concentrated. The concentration degrees of blockchain technology patents in various provinces and cities are different. The patents in the eastern region are more scattered, but the patents in the western region are more concentrated. In response to the conclusions of the analysis, the government should introduce policies to avoid excessive concentration and decentralization of patents. Among them, the eastern region should promote the formation of patent pools, integrate blockchain technology resources, and the western region should strengthen the transfer and transformation of patent results, and promote technology to flow toward the market. Companies should make breakthroughs in incentive layer technology to increase R&D efforts, and appropriately promote patent concentration in the data layer and application layer. Universities, research institutes and enterprises should jointly conduct research and establish a cooperative and sharing technological innovation system.