This paper studied the effects of different film mulch and ridge-furrow cropping patterns on the yield formation and water translocation of rainfed potato in the semi-arid area of west Loess Plateau. Comparing with those under traditional harrowed bedding without film mulch (T1), the potato yield under harrowed bedding with film mulching (T2), completely mulched alternating narrow and wide ridges with furrow planting (T3), completely mulched alternating narrow and wide ridges with ridge planting (T4), mulched raised bedding with furrow planting (T5), and mulched raised bedding with bedding planting (T6) was increased by 50.1%, 75.9%, 86.8%, 69.6%, and 60. 6%, and the water use efficiency (WUE) was increased by 47.0%, 82.7%, 84.0%, 75.2%, and 54.3% respectively, with the increments being the highest under T4 and T3. All the film much and ridge-furrow cropping patterns improved the yield component of potato, and T4 and T3 were most beneficial to the increase of mid and big tubers, tuber number per plant, and tuber yield per plant, and to the decrease of the proportions of green and blet tubers. It was concluded that completely mulched alternating narrow and wide ridges with ridge planting (T4) and completely mulched alternating narrow and wide ridges with furrow planting (T3) were the two better cropping patterns in water-saving and high yielding for potato cultivation in semiarid areas.