Abstract: Profit estimation for the mechanization in agricultural industry is useful to understand the development level, potential, trend of agricultural mechanization for government decision making and it is also an answer to how to estimate the single factor's influence on a complicated economic system. Based on analyses of the productivity theory and methods, two methods were developed to estimate the profit portion of mechanization in the agricultural industry by the Cobb-Douglas production function and a comparison of mechanization and no mechanization in agricultural industry.