In this paper a new way is proposed to determine the generalized stress intensity factors of the plane V-notch structures by boundary element method. Firstly, a small sector around the V-notch tip is dug out from the V-notch structure. Based on the assumption of an asymptotic stress field in the V-notch tip region, evaluation of stress singularities of the sector zone are transformed into an eigenvalue problem of the ordinary differential equations. Then the solutions of the eigenvalue problem provide the singularity orders and associated eigenvectors of the V-notch. Hence the displacements and tractions on the arc of the above sector are expressed as the linear combination of the finite terms of the series expansion with different singular orders. Secondly, the boundary element method is used to model the V-notch structure removed the small sector, in which the boundary conditions along the arc edge from cutting the sector are expressed by the above linear combination. Consequently, the generalized stress intensity factors and the stress field of the V-notched structure are obtained through the boundary element analysis. Finally, two numerical examples are given to show the effectiveness of the present method.