With the development of the new urbanization, the accumulation of local government debt has caused widespread concern of society for these years. According to the form, generating mechanism and transmission mechanism of local government debt risk in China, such debt, virtually, is based on the default debt, the paper constructs an index system of risk prewarning model of local government debt based on the entropy model. Based on quantification of local government debt risk, the paper puts forward some measures for preventing the risk of local government debt in the new urbanization process, and in this way the approach is better than general linear prewarning method, further it can reflect the scale of debt risk effectively and reasonably and provide a new train of thought on debt risk control in theory.