Cold wave weather process is a large-scale strong cold air activity process, will bring drastic cooling and wind, as well as rain and snow weather. This research mainly studies the evolution and cause of a cold wave weather process of China from December 23rd to 26th, 2021. The weather map from the National Climate Center and the geopotential height and sea level pressure reanalysis data from December 23rd to 26th, 2021 provided by National Centers for Environmental Prediction of United States are analyzed by the comparative analysis method and the high altitude situation forecast equation. As a result, this research found that this cold wave was considered a nationwide process. Besides, this cold wave process was mainly caused by the invasion of cold air from Siberia. In addition, under the joint action of the warm high pressure ridge in the Ural Mountains, the polar vortex split and presented a multi-polar distribution. One of them was located near West Siberia, which was conducive to the accumulation of cold air here. With the rotation of the transverse trough, cold air moved southward, and cold wave broke out.