Abstract: To explore the effects of straw mulching on soil moisture and yield of watermelon, corn straw was used as mulching materials, and three straw mulch treatments were performed, i.e., whole mulch (WM), rows mulch (SM) and root domain mulch (RM), and nonmulching as control. The results indicated that WM and RM treatments increased significantly soil water storage in 0-120 cm of soil layer under root domain and rows compared with the control during watermelon growth period, and soil water storage of RM was higher than that of SM after growing tendril. Effects of all straw mulch treatments on soil moisture were most obvious from watermelon postgrowing tendril to preswelling and maturity. With the growth and development of watermelon, the three straw mulch treatments improved soil moisture around root domain, resulting in increased watermelon yields. Compared with the CK, the WM, SM and RM treatments significantly improved the yield and the water use efficiency of watermelon by 24.8%, 11.5% and 15.1%, and 42.7%, 24.3% and 29.4%. The WM with 13500 kg·hm^-2 straw was recommended for watermelon production in arid areas due to its favorable effect on soil storage moisture, yield and water use efficiency.