In metal mold casting, the blowing cooling time after mold opening often needs much production to be determined. To reduce production cost, numerical simulation is proposed to replace the traditional trial-and-error method. The cycle casting process of aluminum alloy wheel castings with low pressure casting was simulated by using the cycle casting function of the commercial simulation software ProCAST. By setting different blowing cooling time, analysing the equilibrium time and period, and the equilibrium temperature field of castings and molds, a reasonable cooling process scheme can be selected. Considering the production benefit, die life and casting quality comprehensively, it is the best scheme when the mold cooling and blowing time is 50 s. The results show that using this method to determine the mold cooling process can provide scientific theoretical guidance for the actual production of casting.