Risk assessment of debris flow in the Hongchun Gully of Shanyang County, Shangluo City, Shaanxi Province was studied. Risk assessment of debris flow under different rainfall conditions was carried out by employing the methods of quantitative calculation and data normalization. Intensity index was introduced to characterize the scale and potential ability of damage. Results show that the probability of debris flow occurrence is 100% when rainfall reaches 198.4 mm or more in 6 h. The level of debris flow risk is low when daily rainfall (r) reaches 37.19 mm; the level is middle when the r is 64.34 mm; the level is high when the r is 104.94 mm; and the level is very high when the r is 282.74 mm.