Abstract: Nearly 80% area of the Nam Ou River Basin in Laos is plateau and high mountains, where the annual rainfall is abundant and mountain torrent disasters occur frequently. Due to the imperfect prevention system of mountain torrent disasters in Laos, mountain torrent disasters often cause heavy casualties and property losses. It is necessary to preliminarily establish a mountain torrent disasters prevention mode in Nam Ou River Basin, Laos. In this paper, the division of vulnerability zones and reasons of mountain torrent disasters in Nam Ou River Basin were analyzed. The graphic layer algorithms of FFPI and CN were used to analyze the risk distribution of mountain torrent disasters. The prevention mode of mountain torrent disasters in the Nam Ou River Basin was proposed according to the non-engineering measures such as the water and rain monitoring equipment and the early-warning system of mountain torrent disasters. The results showed that the area of medium-high vulnerability area accounted for 54.3% of the total area in the Nam Ou River Basin, especially the Ph?ngsali Province in the northern area had the most severe vulnerability. The risk distribution of mountain torrent disasters gradually decreased from northwest to southeast. The research results can provide scientific and technical support for the construction of mountain torrent disasters monitoring, pre-warning, and prevention systems in Laos.