Abstract: Based on the survey and analysis of underground debris flow,and using the combining method of expert-level questionnaire survey and the analytic hierarchy process,the factors of underground debris flow formation are researched,and the indicator system of influencing factors about the underground debris flow is established. Studies showed that the factors,such as rainfall and continuing days,soil thickness and its characters,surface subsidence,mining,surface water played the vital roles in the formation of underground debris flow,then providing a theoretical basis on forecasting the occurrence of underground debris flow.

Key words: Underground debris flow, Influencing factor, Indicator system