The initial problem of one dimensional diffusion equations can be solved by using global or sub domain high precise integration method.One point high precise integration method is the simplest case of this method.When the exponential function in this method is replaced by different expressions of its approximation,this method is transferred to different finite difference methods.Comparative study of these two methods is made in this paper.Different kinds of finite difference method can be expressed in terms of the corresponding approximations of one point high precise integration method.