The work aims to mine more comprehensive user demands from big data to optimize the design of pet cat air carrier products. A research method was proposed based on big data mining to obtain the user demand of pet cat air carriers and analyze it. Firstly, the UGC platform comments were semantically extracted and processed; Secondly, a demand element model was constructed to analyze the relationship between user demand features and visually present them; After that, the user portraits were drawn through user information data mining and qualitative research; Finally, the user demand features and user portraits were integrated to construct a user behavior map, summarize the overall user demand, and transform it into design demands to guide further design practice and case validation. The design demands were mapped to functions and solutions. And on this basis, the design and development of pet cat air carriers were carried out. Afterwards, the feasibility was verified in conjunction with user satisfaction testing. In conclusion, the experience evaluation of design practice shows that the combination of the big data mining and qualitative analysis of user demands can effectively and comprehensively obtain user demands. It provides a scientific basis for subsequent design optimization research.