The mechanical system′s intrinsic structure may influence the long time computation′s accurate and stability. The discrete variation integrators can conserve the energy momentum and the symplectic structure of the system. Combined with the discrete variation principle, the discrete variation integrator method can be obtained through the process of discretization varaiton and integration. This is a recursive algorithm that the time history of the parameters only need the initial condition. According this theory, a sympletic-momentum integrator can be formulated for the holonomic constraint Lagrange system. This method can get the recursive formula of the attitude and the angle velocity direct form the discrete Lagrange function and don′t need complicated iterative computation. The discrete variation integrator method explored in this paper is based on the first Lagrange function. The spherical pendulum is a Lagrange system with holonomic constraints. The simulation result states that the energy be conserved in a long time simulation, and the accuracy of the computation presents a quadratic relation with the time step. The angle velocity and the attitude also present different character under two different algorithm.