Magnesium and magnesium-based alloys are important lightweight metal materials, which are widely used in automobile, communication, aviation and other fields. Due to the high thermal expansion coefficient of magnesium alloy, the assembly precision and mechanical properties of magnesium alloy are easily reduced when it is applied to precision devices. Therefore, low thermal strain magnesium-based materials need to be developed to meet the requirements of such applications. In this paper, the principles and methods of reducing the thermal expansion coefficient of magnesium alloy are reviewed, and the main methods of adjusting the thermal expansion coefficient of magnesium alloy, such as alloying, composite materials and special processing technology, are summarized and compared. The methods of reducing the thermal expansion coefficient of magnesium alloys, such as alloying with high melting point elements, doping with high hardness particles, doping with low thermal expansion coefficient fiber and heat treatment combined with extrusion processing, were summarized, and the future research trends in this field were prospected.