According to the spatial stress characteristics of circular diaphragm wall，the influence factors and rules of spatial effect of circular diaphragm wall were analyzed through theoretical analysis and numerical calculation. The moment theory of cylindrical shell was applied to the circular diaphragm wall，and the analytical solutions of the internal force and deformation of the circular diaphragm wall were obtained. The basic physical model of circular diaphragm wall was established by Midas GTS. By changing factors such as the excavation radius，wall thickness，embedment depth， lining thickness and soil parameters，the stress and deformation law of the structure are analyzed. The results show that excavation radius and wall thickness have great influence on spatial effect. While the effects of embedding depth，lining thickness and soil layer are small. The findings can provide reference for similar projects.