Molding parameters are significant for compression molding. In this paper, the molding process for low pressure sheet molding compounds thickened by crystalline unsaturated polyester was investigated. The optimal molding parameters such as molding temperature, molding pressure and curing time were determined by orthogonal test. And the effect of molding parameters on flexural strength and surface quality of molded parts were also studied. Results showed that when the molding temperature was 115°C, the pressure adding time was beginning at 15s after LPMC was put into the die cavity, the moving time of press column was 15s at the last 25mm and the pressure keeping time was 6min, LPMC gained optimal mechanical property and surface quality.