This paper investigates the scale and expression of passengers’ anger from the disputes between drivers and passengers, as well as among passengers on the bus by surveying a sample of 757 undergraduate students. The bus passengers’ anger scale and expression inventory (BPASX), a newly-designed questionnaire battery, is used to analyze anger levels and resulted behavior expression of passengers in 6-item anger-provoking situations. The analysis shows that a positive correlation exists between the frequency or duration of bus rides and anger levels/ external anger expression, while self-adaptive expression is only correlated with the frequency. Gender differs only in the violent external expression where males display a greater preference. Meanwhile, the correlations of anger levels among anger-provoking situations are significantly positive. Moreover, anger expression patterns gradually shift from self-adaptation to external expression as anger levels grow in general, but the variation rules of expression frequency are different. Overall, this study provides a newly effective tool to explore characteristics of anger expression of bus passengers under different anger-provoking scenarios and demonstrates its variation features when anger levels change.