As an importantly functional and safe part of automobile, gasoline tank is gradually made by plastic instead of metal. To shorten the production cycle time and increase the output of plastic automobile gasoline tank, its cooling and solidification can be put on special fixture by wind or water after being taken from mold. An automatic plastic gasoline tank water-cooling equipment was designed with Solidworks software. The operation procedure was automatically controlled by program instead of manual work. By using PLC as control center and touch-screen as man-machine interface, the control system can be carried out to solve the difficulty of setting the technical parameters, such as water temperature and cooling timeless. The results show that the production output was increased and production quality was improved effectively.