Abstract: The seasonal characteristics of soil physical and chemical properties under different grazing patterns (annual grazing, winter grazing, no-grazing) were studied on an alpine wetland of the eastern Tibet Plateau. The main results were: soil moisture and soil organic carbon content at the surface(0-15 cm)and sub-surface (15-30 cm) layers were highest under non-grazing and lowest under annual grazing. 2) For all treatments, soil moisture, organic carbon, total nitrogen, total phosphorus and available nitrogen significantly declined with increasing soil depth, however, available phosphorus was not affected by soil depth. 3) The surface soil organic carbon content of all treatments showed the same seasonal pattern; September>May>July and soil total nitrogen and total phosphorus content were generally higher in September. 4) Total nitrogen content in both soil layers were significantly positively correlated with soil organic carbon content in July and September. It is concluded that annual grazing increases carbon, nitrogen and phosphorus cycling and increases nutrient losses, leading to decreased soil fertility and declining grassland quality.