The mold cavity structure of mobile phones is one of the most typical complex surface structures. Specific to this type of product, this paper takes some typical product as an example, to conduct Hyper Mill-based analysis and computation for surface processing quality control problem in numerical control milling on the basis of the analysis of traditional mobile phone cavity processing. The description of five-axis processing and path as well as VERICUT simulation is explained with the final application verification. The result shows that the quality control formula of the processing surface is consistent with the actual situation, and the advantages of five-axis processing technology in the application of such types of products are clarified as well.