The great leap famine started with a good harvest in the end of 1958 and ended when the rural grain consumption per capita touched the lowest level in 1961. All the hypotheses except for communal dining halls could not explain the puzzle. The communal dining system is the most important cause of great leap famine since it can explain the whole sequence from the start, aggravation and end of the famine. Basing on the panel data from 1958 to 1962 of 25 provinces, and employing the sharp change of the participation rate from elementary cooperative in 1954 to advance cooperative in 1956 caused by Mao’s critique on Deng zihui in 1955 as the IV of the radicalism of communal dining system, we find that communal dining system do have greatest partial effect with high significance on the death rate than the other factors. The evidence of the beta coefficient and Gfields decomposition also show that communal dining system is the most important cause on the famine.