Abstract: According to the structural characteristics, material characteristics and plastic appearance quality of an automobile side apron as well as the requirements for batch production, a large complex injection mould with a hot-runner-plus-common-runner structure was designed. An optimal design proposal for gating system was determined as a 5-point hot runner feed system through a careful mold flow analysis, and the feed sequence was adjusted by the sequence valve according to the quality of molded parts. It was confirmed that the side core pulling mechanism of the die was complicated, the temperature control system was balanced and efficient, and the guide positioning system was accurate and reliable. The results indicated that the molding cycle could be controlled within 75 s and the dimensional accuracy of plastic parts achieved MT4 thanks to the advanced design and reasonable structure for the mould developed by this work. The mould was kept a stable operation since the formal production.