In a Stipa breviflora desert steppe of Inner Mongolia a long-term positional grazing test with different stocking rates was carried out. Sheep grazing started from year 2002 till to 2008 and grazed from June on to October in each growing season. The grazing test was randomly designed with three blocks and soil samples were collected for seed check. The results illustrated that soil seed bank density was significantly affected by different stocking rates, showed a decreasing trend with increasing stocking rate. In all grazing plots the seeds mainly concentrated in the 0~10㎝ soil layer.