This study develops a risk assessment methodology for assessing the regional environmental risk associated with multiple hazards, multiple areas, multiple receptors, multiple exposures and public participation. This article develops a process for environmental risk assessment and testes it through a case of Yangmingshan national park. Using a combination of historical records, remote sensing data, survey data, and GIS techniques, the results of the case show the characteristics and spatial distribution of the environmental hazards, vulnerability and risk over the area. The analytical results also reveal a number of sub-areas with the greatest need to reduce their risk. The findings provide environmental planners or managers with a useful basis for decision-making regarding environmental risk management.