In the conditions of different treatments,studies were made of the variation laws of the colonization rate and colonization intensity when arbuscule mycorrhical fungi(AMF) colonizated Betula albo-sinensis.The result showed that in the natural condition,AMF's colonization and colonization intensity were high.Illumination intensity strengthening increased AMF's colonization and colonization intensity.Temperature rising and carbon dioxide concentration diploidizing promoted AMF's colonization intensity.Treatment of 4~7℃ higher than the present temperature would promote AMF's colonization.Treatments of 2~4℃ higher than the present temperature and carbon dioxide concentration diploidizing were inhibitoryin summer and promotive in autumn.From summer to autumn,AMF's colonization descended,but carbon dioxide concentration diploidizing would increase AMF's colonization.