To analyze the mechanisms of growth and fluctuations in Chinese agricultural production after the Economic Reforms, we surveyed the process of rural economic reforms and the changes in the agricultural environment since 1978, then estimated the stochastic frontier production function of farming sector using the panel data from 28 provinces for 1980-1995. Based on these results, we also made a growth accounting analysis. The following findings appeared: 1. In the whole period covered by our research, the growth in farming production was supported mainly by modern inputs such as chemical fertilizers and farm machinery, but the fluctuations were dependent on the efficiency in production process. 2. For 1980-1984, Chinese farming production grew rapidly. About 52% of this growth came from the increase in inputs, 42% was due to the improvements in production efficiency brought about by introduction of the responsibility system. 3. However, the growth of farming production soon slowed down after 1985. Little part of this slowdown was attributed to inputs and climate conditions, while the majority was due to the fact that the contributions made by the responsibility system ceased, trade terms took a turn for the worse. 4. Starting in 1990, we noticed a slight increase in the growth of farming sector. The reason for this improvement was mainly due to the improvement of trade terms and the increase in government expenditures on agriculture.