Abstract: Based on the investigation and analysis of 85 major coal mining casualty accidents in China from 2010 to 2016, we conduct human factor analysis and classification system (HFACS-MI) of the improved coal mining, and systematically analyze the unsafe behavior of coal mine employees, the external factors that affect unsafe behavior, organizational influence, leadership behavior and preconditions. On the basis of this, the internal relation between each level of HFACS-MI frame is analyzed by chi-square test and odds ratio. The results of research show that: in the external factors, management factors have the most important impact on China's coal mine accidents, and it can easily lead to loopholes in organizational processes and other issues; in organizational influences, poor resource management is the most prone to problems, will lead to inadequate supervision and improper operation plan; leadership behavior mainly for unsafe supervision violations, is an important reason for team resource mismanagement and poor mental state; the main premise of unsafe behavior occurs for poor mental state, it can lead to cognitive errors, decision-making errors and violations; illegal operation is the most prominent in the performance of unsafe behavior.