This article qualitatively and quantitatively analyzed the main factors influencing the strength of composite coated products and put forward the problems that should be paid attention to in the process of laminating machine and many beneficial suggestions for the improvement of composite strength. Using the orthogonal test method in mathematical analysis, this paper tried to find the optimal process parameter to improve composite strength. The optimal intuitive process parameters were as follows: composite temperature of 90 ℃ , composite pressure of 20 MPa, and compound rate of 800 r/min. The optimal process parameters for the bit level were composite temperature of 80 ℃, composite pressure of 20 MPa, and compound rate of 800 r/min. The possible optimal process parameters were composite temperature of 80 ℃, composite pressure of 25 MPa, and compound rate of 800 r/min. The scope of reasonable technique selection for ink layer thickness was lithographic printing ink layer thickness in 0~3 microns for selecting coated processing. The composite temperature could be generally 85~95 ℃ and should be increased when the ink layer was thicker. And the composite pressure could be set as 20~30 MPa, the composite speed 500~700 r/min. Through selecting the best parameters, the strength of composite coated products was improved.