Human factors under emergency state play a crucial role in evolution of accidents. Studying human factors under emergency states has theoretical and practical significance for prevention and reduction accidents. The study put forward an analysis framework about human factors under emergency states: "Human-System-Environment-Task-Organization" to qualitative and quantitative analysis accidents caused by human factors. Based on the framework, Human-HAZOP analysis and Bayesian network were adopted for the human factor analysis. Human-HAZOP relies on guidance words and attributive words, revealed consequences of human error and proposed preventive measures. Bayesian network graphically modeling accident caused by human error, quantitatively analysis interrelationship between human factors, finding the most contribution cause chain of accident. The framework was used to assess storage tank accidents and analyze the impact of the human factor under emergency states. The study proposed a systematic way to analyze the accident caused by human factor, which will contribute to preventing the accidents under emergency states.