Abstract: This paper discusses the principales of debris flow risk zonation,i.e. similarity,integrity,factor synthesis and factor dominancy.Regional grade of debris flow risk is chosen as the synthetic index for the risk zonation and the method for risk grading is also given here. Based on the grades,five zones,negligible risk zone,low risk zone,medium risk zone,high risk zone and very high risk zone are differentiated. Taking Zhaotong county of Yunnan province as an example,the paper describes the methods of debris flow risk zonation and achieves the debris flow risk map for Zhaotong county.