Abstract: Combined with the requirements for automatic formation and also considering ofa difficulty in mold release, an injection mold with one cavity with 2point gates and three plate die was designed by means of CAE analysis and CAD structure-aided design technology. Two point gates were designed for the injection mold cavity, and the exhaust of the cavity was carried out by using the gap between the inlay pieces with a dimension less than 0.02 mm. A 14-independent-waterway system was adopted for the cooling system to ensure the uniformity of shrinkage deformation for the plastic parts. To overcome the difficulty in demolding of plastic parts, three cylinder-driven slider mechanisms were designed to conduct the demoldingof the characteristic exterior walls, and a composite mechanism with 8 sliders and 6-time pulling core was designed to conduct the core-pulling demolding of the characteristic interior walls. In the inner-wall demolding mechanism, the first cylinder drive completed two core-pulling operations and one slider displacement at first and then completes partial demolding. This provides a space for core-pulling action and the subsequent core-pulling action of the slider. Furthermore, the second cylinder drive completes one core-pulling operation and two core-pulling operations, thus realizing the complete non-interference demolding for the inner wall of the plastic parts. With a reasonable structure, this mechanism has a reliable operation and good practicability.