Contract law in turn has undergone three successive theoretical phases: classical contract law theory, neo-classical contract law theory and modern contract law theory. Aiming to solve relational contract problems, modern theory of contract law includes different kinds of new contract theories, and embodies contract theory’s latest development status and trends. Macneil’s relational contract theory is the most eye-catching one, and it is called “the most promising basis for the construction of the alternative jurisprudence of market transaction following the death of classical law of contract”. But there are many difficulties both in theory and practice that relational contract theory couldn’t overcome. The advanced western contract theory provides a nice reference for the modernization of China’s contract law, but also presupposes its limits and difficulties.