Passenger transport service has developed qualitatively and quantitatively in recent years. Besides inter-province bus transport companies that supply professional and high-quality services, many public transport companies fail to satisfy their customers. To reduce the gap between expectation and perceived quality, this research tries to analyzes factors that affect the quality of inter-province public transport service employing both qualitative and quantitative methods, including Cronbach's Alpha, EFA and multiple linear regression analysis. The results identify five factors that affect the quality of the high-quality inter-province transport service as follows, in order of importance: (1) Safety and comfort: (2) Line networks: (3) Information and customer communication services: (4) Networks of destination, departure and rest stop points: and (5) Accessibility. Conclusions and managerial implications are offered to help suppliers of high-quality inter-province transport service figure out measures to improve the service quality.