Ecological risk refers to the possibility that various stress factors arising from natural disasters and human activities in a given region affect a complex ecosystem, including reductions in health, productivity, genetic structure, and economic and esthetic values of certain elements or the entire ecosystem. In the complex environment of Southwest China, conflicts between people and land are prominent, and the ecosystem faces various risk stressors. Therefore, it is of great significance to carry out ecological risk assessments for the early warning and prevention of regional ecological risks. Considering the characteristics of Southwest China, we divided ecological risks into natural disaster risks, namely, drought, flood, earthquake, landslide, debris flow, soil erosion, and rock desertification, and human activity risks, namely, population pressure, economic pressure, water pollution, and soil pollution. Seven ecosystem types were used as risk receptors-forest, shrub, grassland, wetland, farmland, bare land, and urban. A single risk assessment model was constructed using three components:danger of risk source, potential ecosystem loss, and ecosystem vulnerability. The model spatially superimposed the results of a single risk assessment to obtain the comprehensive ecological risk value of the Southwest. Moreover, the dangerousness of risk sources was quantitatively analyzed using relevant environmental impact factors, and the degree of potential ecosystem loss was characterized by ecosystem quality. Ecosystem vulnerability was analyzed based on two aspects:environmental vulnerability and landscape structure vulnerability. The results showed that the area of high ecological risk in Southwest China measured 170200 km², accounting for 7.4% of the study area. High risk areas were mainly distributed along the mountains and hydrographic net, such as the Nianqingtanggula, Qionglai, Ailao, and Wuliang mountains and the Jinsha, Nu, Lancang, and Dadu rivers. These areas are geographically complex and prone to natural disasters. Therefore, geological readjustment, prevention, and monitoring should be strengthened to minimize the losses caused by natural disasters. The National Natural Forest Protection Project and Sloping Land Conversion Program should be continued to reduce the vulnerability of ecosystems and to improve ecosystem ability to resist risks. Ecological risks to Chengdu, Chongqing, Guiyang, and other cities (and their surrounding areas) are also relatively high because of their dense populations and strong human interactions. Therefore, to reduce the economic and population effects on ecosystems, efficiency of land use should be improved, human over-exploitation should be controlled, and industrial structure should be optimized. Although ecological risk is low in Northern Qinghai and Tibet, the ecological environment is highly vulnerable. Hence, ecological environmental construction should be enhanced to prevent the destruction of original fragile ecological environment.