Through the investigation into distribution of diameter , density and cover of ant mound on mobile dune of Horqin sandy land , the effects of microrelief on nest building activities of Formica cunicularia and the activities on soil properties were analyzed in the research . The main results were as follows : the disribution of diameter , density and cover of ant mound differed remarkably on ridge , mesoslope , and downslope of the windward and leeward slopes . The diameter of ant mound on mesoslope of windward slope was smaller ,and the order of density and cover was ridge > mesoslope > downslope . On the other  hand , t he nest building activities changed the soil properties : the soil water content , electric conductivity , organic matter and total N increased while pH decreased ; in terms of microrelief , the ant mounds on the downslope of windward slope had higher water content , that on the downslope of leeward slope had higher organic matter , and that on ridge had lower pH and electronic conductivity. The variance of micro-habitat of different slopes had important effect on t he nest building activities , but the correlation between microrelief and distribution of ant mound was not obvious as a whole ( P > 0105) .