Based on the features of DE-GMAW (double electrode gas metal arc welding), a new hybrid heat-source model that is suited for the DE-GMAW is established. Using this heat-source model, the temperature fields of DE-GMAW wtih different welding parameters are simulated. According to the simulation results with different welding parameters, in this article we analyze the influence of welding parameters on the heat input of base metal in DE-GMAW. To verify the rationality of the hybrid heat-source model of DE-GMAW, the simulation results of the temperature field are compared with the results obtained from the experiment that is carried out under the same condition. The research results indicate that under the same total current, the heat input of base metal decreases gradually with the increase of by-pass current. Moreover, the closer to the welding line the greater the decrease rate of the heat input of base metal is. The study and the comparison of the thermal cycle curve of measured points show that the simulation results are in good agreement with the experimental results. These results indicate that the temperature field model is accurate and the hybrid heat-source model is reasonable.