Abstract: Landslide and mndflow often lead to the special natural disaster in the economical construction of mountainous areas. This paper has expounded that disastrous mudflow is caused by the highspeed landslide in Qikuo, Huaying city. Among the factors of its influence, besides lithological and geological structures, the most important is the changes in the atmospheric and undergrund waters, which result in the formation and expansion of mudrock creep zone in the mountainus rock. In addition, the thunderstorm and drenching rain are the cause of huge mudflow.

Key words: Mudflow, Disastrous geology, Landslide of mountainous rocks, Changes in underground water, Creep zone