Regional landslide hazards assessment is the basis of the research on regional landslide hazard risk.A “black box”method is proposed based on inverse distance weighted interpolation（IDW）theory consideringlandslide as a system and the factors as subsystems.This approach hypothesizes that existing landslides havelocal influences on the landslide risk to their surrounding areas according to the principle that the more closedthe distance of the things is,the more similar the characters of them are;it obtains the result of regional landslide hazard assessment by analyzing all the landslides with the IDW theory;and simultaneously,it analyzes the basis of theory why the IDW theory can be applied in regional landslide hazards assessment and thescope of its application.Finally,the feasibility of IDW Interpolation theory in regional landslide hazards assessment is verified by taking Cangxi County of Sichuan Province for an example.