Abstract: A method of combining back propagation neural network (BP neural network) and genetic algorithm was proposed to optimize the pressure curve in order to improve the volume shrinkage at ejection and the warping of bi-color products. Using the method, the optimal pressure curve could be obtained: PP holding pressure 55 MPa, holding time 12.5 s, ABS holding pressure 75 MPa，holding time 3.5 s. Finally, the CAE simulation was simulated under the optimized parameters. The target variable was 4.411，less than the experimental scheme. And the warpage of bi-color products was reduced from 1.696 to 0.7427 mm.