As an effective alternative approach to provide goods and services for public infrastructure, the Public Private Partnership(PPP) has been studied extensively over the past few decades. On a global scale, China and the United States have developed cooperation on PPP projects in various areas. To perform a comparative study, this paper analyzes how PPP projects work in both countries for public transportation. The basic features, types, and phases of PPPs in public transportation are introduced first, followed by a thorough discussion on their advantages and challenges. This paper adopts a case study method to analyze the achievements and problems of PPP projects in both countries and then proposes important findings and suggestions for future research. As an effective alternative approach to provide goods and services for public infrastructure, the Public Private Partnership (PPP) has been studied extensively over the past few decades. On a global scale, China and the United States have extended cooperation on PPP projects in various areas To perform a comparative study, this paper analyzes how PPP projects work in both countries for public transportation. The basic features, types, and the phases of PPPs in public transportation are introduced first, followed by a thorough discussion on their advantages and challenges. paper adopts a case study method to analyze the achievements and problems of PPP projects in both countries and then suggest important findings and suggestions for future research.