The strong disturbance caused by human engineering and the impoundment of reservoir leads to risk of landslide and impulse wave generation in most of the reservoir towns in the high susceptibility geo- disaster areas. There is historical documentation of tragedies caused by these disasters. In this paper, six steps for risk assessment of landslide- induced impulse wave near cities and towns in mountainous reservoirs, including investigations on potential tsunami sources, deformation and research failures, impulse wave hazard analysis, vulnerability investigation, risk assessment and risk mitigation countermeasures analysis, are constructed. Taking Wushan County in the Three Gorges Reservoir area as an example, the Longmenzhai rockfall nearest to the county was selected for technical demonstration. The volume of this columnar dangerous rock mass is about 30. 4×104 m3, which is in the state of under- stable and basic stability. The analysis of particle fluid coupled numerical model shows that a maximum impulse wave of about 17. 9 m and 11. 6 m will be generated by collapse of this dangerous rock body under water level of 145 m and 175 m, respectively. The dense wharf ships and frequent tourist ships are mainly risk receptors in the Wushan County. The probability of exposure of tourist ships to waves is 3. 4×10 -4 /a, which exceeds the acceptable risk limit. The potential direct economic loss of Tourist Wharf and Gucheng Wharf caused by the impulse waves is large (more than 2 million RMB), and the pontoon personnel of each major wharf in the county has a high- extremely high risk. In view of the current case, four specific mitigation schemes are discussed. Relevant research can provide technical support and reference for geo- disaster prevention and mitigation of reservoir towns in mountainous are as around the world.