Abstract: A relative risk model was constructed for environmental risk analysis of suburban agricultures consisting of different types of habitats and risk sources, by using a rating system to evaluate risk sources and habitats in the study zone and analyzing interactions between risk sources, habitats and risk receptors. A case study was conducted of Changsha City. In the study, the suburbs of the city were divided into nine risk evaluation units in light of with their administrative boundaries, and five types of habitats (cultivated land, vegetable garden, woodland, grassland, and waters), three risk sources (crop farming，livestock breeding and rural daily life) and three assessment endpoints (water quality, soil quality and biodiversity) were set for quantitative environmental risk assessment of the suburban agricultures of Changsha. Results show that Yuelu District is a high risk area with a relative integrated risk value being 108.11，Tianxin District and Furong District are mederate risk areas, and the others ( Kaifu District, Yuhua District, Changsha County, Ningxiang County, Wangcheng District and Liuyang City) are low risk areas. Environmental risk is greated in the suburbs than in the outer suburbs, especially the stress from farming activities. In the outer suburbs, farming is the primary risk source and among the habitats, waters are under higher environmental stress. Although primary risk sources vary from area to area, farmlands are subject to greater environmental stress than the other habitats.

Key words: suburban agriculture, environmental risk assessment, relative risk model (RRM), Changsha City