Inclusive finance is a development direction of current finance reform for the nations of the world. Based on the theory of inclusive finance, this paper analyses the credit risk of middle and small-sized enterprises in China through KMV model. In empirical analysis, we choose the sample data coming from ST company, *ST company and non-ST company in the growth enterprise market of China. After calculating the default risk and the default probability of enterprises, the results show that, in general, the enterprises in unnormal operation have higher default risks relative to the enterprise in normal operation. According to sample data, individual enterprises in unnormal operation also have lower default risks. In the inclusive financial system, governments should pay more attentions to the development of middle and small-sized enterprises, and establish some proper measures to provide financial services for middle and small-sized enterprises, especially for enterprises in unnormal operation.