This paper discuss the Gauss-Seidel iterative method to solve the large linear system by using matrix iterative analysis and comparison theorems, make the nonsingular matrix ( preconditioned matrix )to left multiply the linear system two-sided. This article pull in the parameter to splitting the new coefficient matix, then prove the improved method not only to accelerate the Gauss-Seidel iterative method, but also to excel the general preconditioned method. Last the numerical example is given.