The purpose of this paper is to deeply analyse the changes caused by the planting structure of grain crops from the supply perspective between 1993 and 2016.First, the paper introduces the background and progress of the pricing mechanism reform of grain crops. Then, the paper establishes the supply response models of rice, wheat, corn, and soybean based on the Nerlove model. It uses data from 1993 to 2016 to analyse farmers supply responses to the changes in the main influencing factors from three levels: the whole country, the main production areas, and northeast China.Findings are that the short term and long term supply elasticities of the sown area to the prices for rice and soybeans are far less than corn and soybeans in both the main production areas and northeast China. Market price supports for rice should be quickly reformed because of the price marketization of corn and soybeans, or else the problems that happened with corn may happen with rice in northeast China. Acknowledgement : Thank you for Dr Li's advices on the models and my colleague,Zhu's endeavors in colecting data.