Abstract: Technological progress in grain production is one of the main driving forces to increase grain production，but the economic surplus brought by technological progress is unevenly distributed between producers and consumers. The price elasticity of grain supply and demand is measured by using the relevant data from 2001 to 2015 in China. It is found that the price elasticity of grain supply and demand in China fluctuates greatly on the whole，but the average elasticity is small. The elasticity of supply and demand is -0.102 and -0.196 respectively. According to the welfare effect model of technological change proposed by Akino and Hayami，it is found that technological progress has significantly improved the welfare level of grain consumers，with an average improvement of 1 06.267 billion yuan per year. However ，the improvement of the welfare state of grain producers was not obvious . Finally，the suggestion was put forward to increase grain support and increase the price elasticity of grain supply and demand.