In order to control the thermal stress of forming process, based on “element birth and death” technology of finite element method, a numerical simulation of three-dimensional temperature field and stress field during multi-track & multi-layer laser metal deposition shaping(LMDS) process is developed with ANSYS parametric design language (APDL). The dynamic variances of temperature field and stress field of forming process are calculated with the energy compensation of interaction between molten pool-powder and laser-powder. The temperature field, temperature gradient, thermal stress field and distribution of residual stress are obtained. The results indicate that although the nodes on different layers are activated at different time, their temperature variations are similar. The temperature gradients of samples are larger near the molten pool area and mainly along z-direction. Finally, it’s verified that the analysis results are consistent with actual situation by the experiments with same process parameters.