Based on the monitoring survey data of 120 agricultural operators in six provinces, this paper empirically analyzed the mechanization level of grain primary processing in China in 2020. The results showed that: the mechanization level of grain primary processing is 56.95%, which is higher than the overall mechanization level of primary processing of agricultural products (37.58% in 2019); among the three major grain crops, the mechanization level of rice primary processing is the highest which is about 68.55%, followed by wheat primary processing with about 57.40%, and corn primary processing with about 49.35%; among the three major operation links, the highest mechanization level of grain threshing treatment has reached to 96.61%, the threshing process has basically realized mechanization, the mechanization level of grain cleaning treatment is 36.06% which is slightly lower, and the lowest mechanization level of grain quality guaranteeing treatment is 35.06%. The unbalanced development of various varieties and links is still prominent. From the perspective of varieties, the short board is in corn, and from the perspective of links, the short board is in quality guaranteeing treatment. This study provides a basis for analyzing and judging the level and trend of grain primary processing mechanization in China.