It aims to study the users’ perception characteristics and psychological mechanism for automobile interior quality. From an aesthetic perspective, the concept and theoretical model of automobile interior quality loudness are proposed based on the psychological theory of sound loudness and the inverted U-shaped curve model of aesthetic experience, so as to describe the psychological mechanism of users' perception of automobile interior quality and explain the relationship between quality perception and preference. The steering wheel, one of the automobile interiors, is used as the research object, and the experiments among ordinary and expert users are conducted, so that the data of changes in quality and preference for the object are obtained with the method of scale scoring, and the relationship of experimental data is established through regression analysis. There occurs a quadratic function relationship between the users’ preference for the automobile interior and the quality of the automobile interior, and the relationship conforms to law of mental perception for loudness. Thus, the existence of the loudness is tentatively verified for automobile interior quality. The two relatively independent perceptual dimensions, automobile interior quality and preference, and the former has a positive effect on the latter within a certain range. When exceeding this range, it turns negative. In conclusion, the research on the automobile interior quality loudness can provide the theoretical basis and technical support for improving the quality of automobile interiors.