In order to investigate the effects of maize straw strip mulching on soil moisture and yield in potato field in northwest semi-arid region of China, four trentments (M1: Big ridge black film mulch planting, M2: Maize straw strip mulching on flat planting, M3: Maize straw strip mulching on furrow and ridge planting, CK: Conventional tillage with no straw covered) were conducted to compare the effects of different mulching patterns on the growth index, soil moisture in different layers, potato yield and water use efficiency in two growing seasons field experiment. Results showed that three mulching patterns significantly increased the yield by 11.68%～21.74%, and improved the water use efficiency by 22.82%～48.63% compared with CK. Compared to CK, single plant yield increased 26.02%～48.37%, the height of plant increased 3.18%～12.82%, single plant biomass increased 0.59%～26.49% and water consumption of crops during the whole growth period decreased 55.29～66.21 mm, thus M2 had the best or better effects. In the potato whole growth period, the average soil moisture in 0—200 cm soil layers in black plastic-film mulching big ridge pattern (M1) was lower than CK by 0.89 percentage points in a normal precipitation year, and M1 is higher than CK by 1.30 percentage points in slight drought year. M2 was better than M1 and CK in whether normal precipitation or slight drought year, and it was 0.20～0.89 and 0～1.50 percentage points higher than M1 and CK, respectively. Among them, maize straw strip mulching on flat planting (M2) had good effects on crop growth, yield increase and water use efficiency, which is suitable for promotion in Northwest semi-arid region.