Accurate financial risk assessment is an effective measure to prevent and resolve corporate financial crisis. In this study, a method of enterprise financial risk assessment based on grey system theory is proposed. The method uses the grey system theory to construct the financial evaluation model, and generates the evaluation index system from the two aspects of enterprise financial indicators and non-financial indicators. The particle swarm is improved based on the chaotic model, and the improved particle swarm optimization algorithm is used to optimize the weight of the gray system. Finally, an experimental analysis is carried out with a real estate enterprise data. The results show that the method can effectively complete the financial risk assessment of enterprises and has high evaluation accuracy.