In order to optimize the weld formation and process parameters of DP800 vehicle high strength steel composite welding, based on the response surface method, the mathematical model between the main process parameters and weld characteristic parameters of laser-arc hybrid welding is established, and the analysis of variance is carried out. Aiming at specific penetration depth and minimum penetration width, the laser power, welding current and welding speed are optimized to obtain the optimal process parameters, which are verified by experiments. Results show that laser power and welding current are positively correlated with weld penetration, and welding speed is negatively correlated with weld penetration. With the increase of welding current or the decrease of welding speed, the weld width increases gradually, and the laser power has little effect on the weld width. The accuracy of the model is verified by experiments under the optimal process parameters, and the error rates of penetration depth and width are less than 5%.