The associated integration and unhindered connection between different modes of public governance is conducive to enhancing the legitimacy and effectiveness of governance. The case study of the “Green Travel” governance model change in City Q shows that, the “new era characteristics” of public governance, the “problem orientation” of public governance and the “anti-function” of public governance conventional model constitute the institutional motivation, the systematic motivation and the structural motivation respectively, resulting in the alternation and integration of three modes of hierarchical governance, market governance and network governance. The alternating integration of the three modes has realized the “distinctive combination” of public governance in different realistic scenes. While giving full play to the decisive role of market in resource allocation, it has better played the role of the government and society, thus enhancing the legitimacy and effectiveness of public governance. To further advance this distinctive tendency to correspond to the new governance model of “co-construction, collaborative governance and sharing”, it is necessary to make the authority-responsibility relationship clearly among multi actors while encouraging participation, constrain the “legal injury” of the government while giving full play to its role of “meta governance”, and avoid “technical dependence” while working on the marginal improvement on governance technique.Based on the observation of the “green travel” case of City Q, the modern transformation of public governance modes such as hierarchical governance, market governance and network governance has been empirically tested.