The precipitation process simulation of the medial density cubic alloy was conducted using the microscopic diffusion equation including the coherent strain energy, The results show that the coherent strain energy hinder the precipitation process of the alloy. With the increase of coherent strain energy, the arrangement orientation increase, from spherical-shaped precipitates to elliptical plate. With the increase of coherent strain energy, the precipitation mechanism of medial composition alloys near the high density alloys are changing from the mixture processes which possessed the characteristics of both non-classical nucleation growth and spinodal decomposition mechanisms to the processes which possessed only the characteristics of non-classical nucleation growth.