With the deepening of industrialization and urbanization, infrastructure has an increasingly important impact on the sustainable development of cities, and even becomes a bottleneck restricting the development of modern cities. The reason lies in the shortage of funds for infrastructure construction and insufficient investment and financing channels. In this paper, the traditional infrastructure investment and financing modes BOT, TOT and PFI are compared with the emerging ABS and PPP, so as to explore ways to broaden infrastructure investment and financing channels. China is in the process of industrialization and marketization of urban environmental infrastructure. The diversification of investment subjects brought by enterprise market participation, the continuous development of domestic capital market and the continuous improvement of commercial financing means have created conditions for the diversification of financing means. A city is the political, economic and cultural center of a country or region, an organic whole with people as the main body, relying on the natural environment, taking economic activities as the basic content, constantly operating according to its own laws and extremely close social ties; It is the carrier of human beings' concentrated and efficient use of natural resources, land resources, space resources and intellectual resources to create material civilization and spiritual civilization; It is a social entity integrating facilities construction, operation, management and service. With the deepening of industrialization and urbanization, infrastructure has an increasingly important impact on the sustainable development of cities, and even becomes a bottleneck restricting the development of modern cities. The reason lies in the shortage of funds for infrastructure construction and insufficient investment and financing channels. It is necessary to compare and study the traditional infrastructure investment and financing modes BOT, TOT and PFI, as well as the emerging ABS (Asset Securitization) and PPP (Public-Private Partnership), and explore ways to broaden infrastructure investment and financing. 1. BOT (Build-Operate-Transfer) financing, namely "Build-Operate-Transfer", is essentially a way of infrastructure investment, construction and operation. The most essential feature of BOT is that private enterprise funds are used for public infrastructure construction. Its typical form is: the government of the project host country grants the franchise to the project company composed of one or several investors-raising funds for specific infrastructure projects, operating and managing them within the agreed time limit, repaying debts through project operating income and obtaining investment returns. After the expiration of the agreement, the project facilities will be handed over to the local government free of charge, and the ownership of the project facilities will eventually be owned by the government. Therefore, BOT mode is sometimes called "temporary privatization" process. In short, the word BOT is a brief summary of the typical characteristics of the whole process of economic activities such as investment and financing construction, operating return and free transfer of a project. BOT mode is not only a financing agreement, but also a long-term professional agreement. On the basis of the agreement, the public and private parties establish a partnership to provide economical and efficient services to the public. After the 1970s, no matter in developing countries or developed countries, the government's budget became more and more tight, and the demand for infrastructure became greater and greater, so it became increasingly difficult for the government to be the main body of infrastructure investment, the paper network. BOT, as a new way of investment and financing, meets the general internal needs of developing countries and developed countries. All countries have begun to use this new model for urban construction, and achieved certain results. Such as the Anglo-French Channel Tunnel, the Malaysian North-South Expressway, and the first officially approved BOT pilot project in China-Guangxi Laibin Power Plant. BOT, as a new financing method, has complicated operation process and many intermediate links, involving many problems such as engineering technology, economy and law. It is necessary to avoid the risks in the process of project implementation through standardized operating procedures and relatively perfect franchise agreements. In BOT projects, the most important issues are the financing mode of funds, risk sharing, the structure of funds, the determination of the rate of return and the respective positions of the government and the project company, which are related to the success of the project and the long-term maintenance of the cooperative relationship between the two parties. In addition, BOT project needs to strictly control the construction progress and quality of the project to ensure the smooth implementation of the project. BOT mode is suitable for those construction projects with huge investment, long payback period and stable income after completion. Operating government projects, such as sewage treatment plants, power stations, highways, railways and other public facilities have this feature. Through BOT mode, the government can use private capital to build public infrastructure, reduce the upfront investment in project construction and invest limited funds in new areas under the condition of insufficient funds. At present, BOT model has been widely used in the whole country and has become a mature and effective financing model in commercial city construction projects.