Scale economy is the embodiment of the objective law of market economy and the result of the pursuit of micro subjects. Scale is the external performance of modern agriculture, and efficiency is the internal requirement of modern agriculture. Supporting the development of scale agriculture and benefit agriculture is the foothold of China's agricultural policy and the starting point of policy performance evaluation in the past 40 years of reform and opening up. Based on a brief review of scale agriculture and benefit agriculture, this paper takes Hefei, the capital city of central China as a sample, analyzes the construction, function and performance of its modern agricultural industry support policy system, and puts forward the adjustment and optimization direction and main measures of modern agricultural industry support policy from scale agriculture to benefit agriculture.