By studying the mapping relationship between the modeling features of the body temperature measuring instrument and the users' perceptual images, a body temperature measuring instrument that conforms to the users preference is designed. Based on the research of miryoku engineering theory, the evaluation structure method is used to interview the target users. Through the integration of the collected interview data, the eight charm factors of the body temperature measuring instrument and the 25 specific charm characteristics are extracted. The quantification Class I theory is further used to analyze the mapping relationship between the users' perceptual images and the charm morphological characteristics of the body temperature measuring instrument, so as to clarify the degree of influence of each specific charm morphological feature on the users' perceptual images, and provide design reference for designing the body temperature measuring instrument shape that meets the users' preferences. Based on the experimental research results, the model design of the temperature measuring instrument was completed. And the design results were verified and analyzed through comparative experiments. The results showed that the model of the temperature measuring instrument designed can well meet the users' preferences. At the same time, according to the users' preferences for different perception images of the body temperature measuring instrument, the corresponding charm shape characteristics can be identified in a targeted manner, so a body temperature measuring instrument meeting the users' preferences can be designed.