Therefore, this paper mainly discusses the technology of guaranteeing the quality of the parison from the two aspects of the machine head planning and the completion of the control system. In the design of the head, the modern advanced CAD/CAE technology is used in the design of the flow channel in the head, and the method of numerical simulation of the extrusion process of the head is firstly discussed, including the construction of the control equation, the constitutive equation, the initial value The mathematical model composed of the boundary conditions and the mathematical model is derived, and the finite element solution method of the mathematical model is deduced. Then, according to the aforementioned principles, the process of extruding the parison from the composite head of the 5L double-layer bottle blowing machine was simulated and analyzed by finite element, and the distribution rules of the flow field of each part of the flow channel of the head were obtained. The uniformity, the dispersion of the high viscosity area and the stability of the interface of the co-extrusion area are evaluated on the extrusion performance of the die. The channel structure is optimized, and the results show that the optimization effect is significant. The influence of the molding process parameters represented by the non-Newton index of the material, the inlet flow rate and the inlet volume flow ratio between the inner and outer layers on the extrusion function of the die is further analyzed, which has certain practical guiding significance for the formulation of the extrusion process parameters of the die.