Afrina, Merintan2016-04-272016-04-272016-04-27wahyu sari yenihttp://repository.unri.ac.id/xmlui/handle/123456789/8302This paper discusses the preconditioner for solving the linear system Ax = b, where A is of the form M-matrix. The paper review of Li-ying Sun [Journal of Computational and Applied Mathematics, 181(2005); 336 − 341]. Numerically that the improving modified Gauss-Seidel method, which was referred to as the IMGS method, the spectral radius of the preconditioned IMGS method is smaller than that of the SOR method and Gauss-Seidel method. Numerical simulation using some size of A show that the convergence rate of IMGS method can be increased using the preconditionerenM-matrixspectral radiusSOR iterative methodregular splittingstudent Paper Post Degree