With rapid development of electronics, telecommunications, medical, automotive and other industries, requirements for high precision and performance of plastic products are increasing day by day. Precision injection molding requires not only high dimensional accuracy, low warpage, but also excellent optical properties. Injection moulding is one of the most important plastic molding methods. How to improve level of injection moulding technology, produce high-precision plastic products, and create high value-added products. Injection mold design is an important link.