Abstract: As an important agricultural support policy, direct subsidy of grain has always been the focus of China's concern. In order to study the efficiency of direct grain subsidy policy of Beijing, based on the relevant policy and data, using Cobb-Douglas production function regression analysis, DEA method and Malmquist index, this paper make a study of Beijing Direct Grain Subsidy and its efficiency. Analysis results indicated that: regression coefficient of the direct grain subsidy variable in Cobb-Douglas production function is positive and it passed through the test of significance. It promoted the growth of grain production in Beijing City to a certain degree. The result of DEA indicated that the mean values of comprehensive efficiency of 2009-2011 in Beijing City were 0.909, 0.837 and 0.901. Each district in Beijing has a different subsidy policy, thus different district in Beijing has different characteristics in the efficiency of direct grain subsidy.