he rainfall threshold is the key to the warning of rainfall-induced landslides. Because of the available data in the study area is limited, the threshold value is hard to ascertained, which have influence over the effect of landslide warning. The probability analysis of predictive result is proposed on condition of scant prerequisite as a result. This article analyzes the relevance of precipitation and threshold value of landslides occurrence and accesses rainfall-induced landslides probability by calculating frequencies of landslide occurrence and rainfall-induced landslides. The method of probability analysis is brought forth in the warning of rainfall-induced landslides, which is based on the developed landslide warning system. The credibility of the method is shown by applying it to the modeling of Muchuan county. The application of probability analysis method was capable of effectually improving landslide warning system.