It is demonstrated that the residual stress in the fur face layer of martensite stainless steel treated by laser surface melting(LSM)is not always compressive under the condition of extreme multi-pass laser scanning. The sign of the residual stresses depends on the relative size of melting Pool to overlapping zone. When the surface width of the overlapping zone is larger than half of surface width of the melting Pool, there exists obvious compressive stress in the surface layer, otherwise, too small overlapping zone will result in surface tensile stress.