The paper presents an approach to deal with residual stress intensity factors for surface cracks in a thick plate with butt joints by using line-spring model. Based on the Reissner's plate theory along with continuously distributed dislocation thought, the problem of the thick plate with butt joints is treated with a set of Cauchy-type singular equations, which are resolved by Gauss-Chebyshev method. The numerical results of the present method for the surface crack are compared with those of finite element method, and the compared results show good agreement. It is indicated that the line-spring model is not only reasonable and viable for surface cracks analysis in residual stress fields, but simple and convenience for engineering application.