In order to a realize millimeter-scale terrestrial reference frame, high-precision non-linear maintenance technology must be gradually improved. Firstly, this paper introduces the progress of the establishment of the terrestrial reference frame including the establishment of the International Terrestrial Reference Frame and the epoch reference frames; Then, the research status of non-linear maintenance technology is described, and two ideas for non-linear maintenance of the terrestrial reference frame are pointed out, including the non-linear change modeling of the reference station and the establishment of the epoch reference frames. At last, the paper puts forward a prospect for the construction of the millimeter-scale terrestrial reference frame, and suggests that the ground monitoring network should be appropriately increased and improved, especially in the underdeveloped areas of the southern hemisphere, and the existing frame should be improved by using longer and broader original data accumulation; Increase the data accumulation of coordinate non-linear motion and geocentric motion, and conduct in-depth analysis, to establish an accurate correction model; Identify the noise factors in the coordinate time series as accurately as possible, and establish a grid noise model to more accurately separate the actual signal and noise.