Three major traffic projects: Qinghai-Tibet Highway, Qinghai-Tibet Railway and Qinghai-Tibet Highway under construction distributes in the front of debris flow accumulation fan in Ruoru Village, so it is necessary to assess the risk of debris flow. Based on a detailed field investigation, this paper uses FLO-2D software to study the debris flow risk of Qinghai-Tibet Railway, Qinghai-Tibet Expressway, Ruoru Village and main drainage channel. Based on the historical rainfall data from 1998 to 2018, the 5%, 2% and 1% rainfall frequency and the other eight extreme rainfall conditions of the Ruoru Village debris flow outbreak process were simulated, and the debris flow accumulation characteristics of the key threat areas were analyzed. The simulation was compared with the actual situation, and the accuracy was 68.7%, which is within the reasonable deviation range. In addition, the mud depth, flow rate and frequency of outbreaks were combined to obtain a debris flow risk assessment map to provide recommendations for disaster analysis, early warning and development planning.