Abstract: This paper studied the effects of different mulching modes on the soil moisture in a semiarid rainfed area of Loess Plateau, Northwest China. Seven treatments were installed, i.e., mulching plastic film in summer (T₁), mulching plastic film in autumn (T₂), mulching 5 cm long wheat straw in summer (T₃), mulching whole wheat straw in summer (T₄), mulching plastic film in summer plus wheat straw (T₅), mulching used plastic film after harvest (T₆), and unmulching (CK). In T₆, the soil moisture  in different layers at different crop growth stages was all higher than that in CK. In the other five mulching treatments, the soil moisture  in 0-90 cm layer before flowering stage was obviously higher, but that in 0-90 cm layer after flowering stage and in 90-200 cm layer during the whole growth season was lower than that of CK. The soil moisture  in 0-200 cm layer in T₆ during the whole growth period was significantly higher than that in CK, with a difference of 0.9%, but the soil moisture  in 0-200 cm layer in other mulching treatments was lower. As compared with plastic film mulching, straw mulching increased the soil moisture  in 0-200 cm layer. The soil moisture  under mulching with used plastic film after harvest was higher than that under mulching with new plastic film. As compared to CK, the grain yield of winter wheat with plastic film mulching was increased by 20.3%-29.0%, and that with straw mulching was increased by 5.0%-16.7%. There was a significant positive correlation between the crop productivity and the soil water consumption during the growth period (r=0.77^*).