The flatness of aluminum alloy die casting mold has a great influence on the precision of castings, so we must pay attention to it in the production process. I think Yu Huasheng has done a good job in this regard. First, in the process of machining, we will try our best to avoid surface defects such as knife marks, interlayers and cracks on the mold surface, and then strictly control the manufacturing process in the production process to greatly avoid the phenomenon of surface abrasion of parts. Finally, finish machining and polishing are used to improve the flatness of the die.