Abstract: Soil water content was closely correlated with application and extent of vineyard cover crop in a semiarid area. A permanent inter-row cover crop of Trifolium repens, Medicago sativa, and Festuca arundinacea in a vineyard was compared with clean tillage. Localized observation of soil moisture content in the 0-80 cm layer with TRIME-FM TDR was carried out in the vineyard, and soil physical characteristics of the 0-60 cm layer were investigated using the cutting ring method. After planting grasses, the soil physical characteristics improved, soil bulk density of the 0-60 cm soil layer decreased by 8.5%-9.8%, and total soil porosity increased by 11.5%-13.9%. The soil moisture content of a grass-covered vineyard was considerably reduced in 2006 and 2007 compared with clean tillage and the average soil water content of the 0-80 cm depth was reduced by 2.3%-7.5% and 10.7%-15.9% respectively. The soil water content was severely reduced in a year with spring drought and shortage of soil moisture storage from the previous winter. Soil moisture storage and variation of water storage differed between sward treatments, and the M. sativa treatment had the lowest soil moisture storage.