Both axisymmetric and 3-D models are used to simulate the temperature and stress fields of laser beam welding process of beryllium ring. It is shown that the computed results of two models are identical. The temperature and stress fields can be obtained in the quasi-balance state using the axisymmetric model and in the whole process using the 3-D model. The residual stresses at the start and the end welding are about 20 percent larger than that in the quasi-balance state.