The paper aims to effectively obtain user needs and priorities for home smart air purifiers, further transform user needs into design requirements, identify key design requirements for smart air purifiers, and provide reference for design and improve user satisfaction. First, user needs are obtained through questionnaire surveys and interviews, and affinity diagram method (KJ method) is used to build a hierarchical model of user needs for smart air purifiers, and then rough analytic hierarchy process (RAHP) is introduced to obtain the initial importance of various user needs. At the same time, the fuzzy Carnot model (FKM) is used to determine the various demand categories, and the adjustment coefficient is introduced based on the demand category to adjust the initial importance, and finally the quality function deployment (QFD) is used to transform user needs into design elements. The key design requirements of the smart air purifier are clarified to guide the design of it.Through a more in-depth analysis of the user needs of the smart air purifier, the user needs are transformed into design requirements, and it identified that the design requirements of the intelligent air purifier in the filter module, intelligent detection module, information display module, remote APP control module and wind speed control module are of high importance. And based on this, a design plan is proposed, which has obtained high user satisfaction. The research methods and processes in the paper can provide references for designing products that meet user needs.