With the rapid development of the subway, passenger satisfaction has become an important indicator for measuring the brand value of subway services. Based on the Consumer Brand Equity (CBBE) model framework, the random forest model was used to systematically explore the quantitative influence mechanism of brand-building elements on passenger satisfaction. Data was collected through a questionnaire survey of Chengdu Metro, and empirical analysis was conducted by distinguishing three groups: commuters, tourists, and elderly passengers. The research finds that the brand demands of three types of passengers show significant differentiation characteristics, and there is a significant synergy effect between the punctuality of trains and the promotion of low-carbon and environmental protection for commuters. The identification of tourists" characteristic theme stations has a reinforcing effect on the cultural publicity effect. The interaction between the LOGO recognition of elderly passengers and the service of flight attendants can significantly enhance the perceived experience. It provides empirical support for the application of CBBE theory in transportation scenarios and also offers a decision-making basis for metro operators to formulate differentiated brand-building strategies.