Experiments was done in early, middle and late growth period from 2000 to 2002. The experimental plant materials Artemisia frigida were collected from a series of grazing gradient of Leymus chinensis steppe near the Inner Mongolia Grassland Ecosystem Research Station, the Chinese Academy of Science. The location is 43°33′N and 116°40′E. The altitudes range from 1200 to 1250m. The mean annual temperature is-0.4℃. The annual precipitation is 350mm. The evaporation is four times as much as precipitation. The zonal soil is chestnut soil. Four grazing pressure gradients (sampling site) were chosen on a section from herdsmen residence to the research station (enclosed for 20 years), that is no grazing (CK enclosure site), light grazing (LG), moderate grazing (MG) and heavy grazing (HG). Changes of model of Atemisia frigida populations under the disturbance of grazing were studied. The results showed: height of vegetative shoots and reproductive shoot decreased slowly in light grazing, but decreased rapidly in middle and heavy grazing. With the increase of grazing intensity density of vegetative shoots and adventitious roots increased. The increase of density of vegetative shoots can compensate for the decrease of height of shoots. But regression curve of vegetative shoot density of A. frigida population under different grazing intensities showed that the increase of density of vegetative shoots in heavy grazing had approached to compensational limit. With the increase of grazing intensity length of stolon increased, density of reproductive shoots and the differentiation ratio of reproductive shoots (density of reproductive shoots/density of total shoots) tended to decrease. In the meanwhile, differentiation ratio of vegetative shoots increased. With the increase of grazing intensity the reproductive pattern changed from sexual and asexual reproductive to asexual reproductive mainly, which helps A. frigida population to become constructive species under heavy grazing.