Abstract: Taking the back cover of a best-selling mobile phone as an example, the effects of injection time, melt temperature, mould temperature and holding pressure on the maximum warpage deformation of PC+ABS engineering plastic alloy parts were simulated by MoldFlow software via orthogonal test method, and the optimum injection process parameters were obtained. The trial production was carried out with the optimum process parameters obtained by simulation in order to verify the reliability of the simulation results. The results show that the primary to secondary sequence of injection process parameters that affected warpage deformation of thin-walled parts of mobile phone back cover was injection time, melt temperature, mould temperature and holding pressure. The optimum injection molding parameters obtained by simulation were injection time of 0.40 s, melt temperature of 280 ℃, mould temperature of 72 ℃ and holding pressure of 60 MPa, and at this point the maximum warpage deformation of the part was the smallest with the value of 0.509 0 mm; warpage deformation mainly occurred at four corners of the back cover of mobile phone, and the position beside headphone jack had the maximum warpage deformation. The maximum warpage deformation of the trial-produced product was 0.530 mm with the optimum process parameters, and the warpage deformation location was consistent with the finite element simulation result, which verified the reliability of the simulation results.