Stampede accident in large public events has become one of the contemporary public security disasters. The fuzzy comprehensive evaluation method of risk assessment is helpful to solve the complex problem of multi-factors for safety accident. On the theoretic exploration of crowded stampede both at home and abroad, the paper established a risk assessment model by the Delphi method together with fuzzy comprehensive evaluation tool obtained from fuizzy mathematics method based on weighted average operator, and then analyzed comprehensively “12·31” stampede event in Shanghai. Study showed thnat the evaluation grade coincided with the actual safety situation, and the public safety risk assessment should be relied on by combining the subjective and objective evaluation methods. This method provided a quantitative analysis path for early warning against stampede in large public activities, and it could serve as a critical reference for mass activity risk management.