The solidification process and microstructure of ZL201 aluminum alloy auxiliary frame were simulated by Cellular Automation(CA) method, and the temperature field and CAFE(microstructure simulation) field were established. According to the solid and liquid phase lines of ZL201 aluminum alloy, the six different nucleating surfaces were determined. The simulation results of temperature field show that the nucleation rate and growth rate can be controlled in the most suitable range by oil cooling. The nucleation rate is 1/276 s·cm3and growth rate is 65.2μm/s. The calculation results of thermodynamic phase diagram show that in the formation process of Al3Ti phase, which absorbs covalent electrons from surrounding aluminum atoms. With the increasing of titanium content, the precipitation temperature of Al3Ti increases. In addition, the content of Al3Ti has increased from 0.144mol% to 0.698mol%, and the effect of grain refinement became more and more obvious. Through the simulation of the microstructure of ZL201 aluminum alloy auxiliary frame, the corresponding <100> polar diagram and the experimental metallographic structure, it is shown that the change of Ti content has a significant impact on the grain refinement effect of ZL201 aluminum alloy auxiliary frame microstructure. With the increasing of titanium content, the new phase Al3Ti promotes grain refinement and composition uniformity. It can be seen from the simulated polar diagram of <100> that the increase of Ti content is conducive to the preferential orientation of grains, and the grain refinement is achieved by slowing down the competition among grains. The results of simulation are basically consistent with the metallographic structure obtained by experiment.