Pulse laser welding of AISI 304 stainless steel plate was simulated to optimize welding conditions by using commercial finite element code MARC. Due to geometric symmetry, a half model of AISI 304 stainless steel plate was considered. for the heat transfer analysis, user subroutines were applied to boundary condition. The material properties such as conductivity, specific heat, and mass density were given as a function of temperature and the latent heat associated with a given temperature range was considered. A moving heat source was designed on the basis of experimental data. As a result, Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.