A risk assessment model is constructed for the hazardous materials (hazmat) road transportation combining features of TransCAD traffic forecasts, and based on traffic planning network of spatial analysis and attribute process, the database for path planning of hazmat transportation was set up. Based on the TransCAD platform, this research analyzes the risk value of hazmat transportation in each section of the network, and found the optimal route for hazmat transportation. The rationality of the model and the feasibility of the algorithm are proved by the research.