Abstract: Based on principle of heat transfer,fluid dynamics and physical metallurgy,three-dimensional dynamic weld pool mathematical model of gas metal arc welding (GMAW) with locomotory arc was built.A finite element model was setup based on the mathematical model,and the weld pool temperature was calculated using universal finite element method soft ANSYS.Unsymmetrical mesh was used in the calculation,and influnce of melting drop on the weld pool energy and exterior distortion was considered.Double-apex model of double gauss heat source was adopted and the dead-birth method was used.The error was controlled within 8%.The calculated value and experimental value of weld width and weld depth with different technical parameter were compared.The result indicates that it is credible and feasible using ANSYS to calculate GMAW temperature field and introducing double-apex heat flux.