In this paper, the problem of quantification of spatial competition is solved from three aspects: quantification of spatial competition potency, spatial competition relationship, and spatial competition intensity. In quantification of spatial competition potency, traditional evaluation method and Geographical Information System (GIS) spatial analysis technique are combined for evaluation. The influence factors of spatial competition potency are divided as three categories: limiting factors, characteristic factors, and ordinary factors. Thus, synthesis appraisal is employed to analyses spatial competition potency for all geographical entities in evaluation area. At the time of construction of spatial competition relationship model, the gravity model is referred. Nevertheless, some parameters of traditional gravity model are endowed with new meaning: using spatial competition potency of geographical entity to replace the "quality", and using accessibility to replace the "distance". The process of estimating spatial competition intensity of one point in spatial competition area can be finished through the following three steps: computing spatial competition intensity between each two geographical entities around the point, comparing all spatial competition intensity, selecting the maximum spatial competition intensity as the spatial competition intensity of the point. In order to verify feasibility of the method, rural settlements in Tonglu County are selected as test objects.