Debris flow can be divided into three types according to its outbreak frequency:high-frequency( one or many times in a year),medium-frequency(one time in several to 30 years),and low-frequency(one time in more than 30 years).Low-frequency debris flow often burst fiercely without any anticipation and cause serious harm.Based on the analysis of the data from debris flow gullies with different outbreak frequencies,the characteristics of low-frequency debris flow are summarized.Watersheds with Low-frequency debris flow are characterized by high vegetation coverage and a small number and small-scale of adverse geological phenomena.The groove bed scour of low-frequency debris flow is dominant and erosion rate and sediment transport capacity are high.Understanding the characteristics of low-frequency debris flow has important significance in guiding debris flow prevention.