A field experiment was conducted to investigate the effects of plastic film mulching on spatiotemporal distribution of soil nitrate and maize yield in drylands.Four treatments，including (1) Alternating ridges and furrow，the ridge mulched(RM);(2) Flat plot with mulching(PM);(3) Flat plot without mulching(PNM);(4) Flat plot without planting(CK)，were carried out to examinethe impact of tillage and mulching treatments on soil moisture，soil nitrate content(NO-3-N)，maize biological characteristics and yield.Result showed that soil moisture content under mulching on 0~40 cm layer were significantly higher than that in the treatment without mulching.NO-3-N mainly accumulated in 0~40 cm soil layer under mulching which the NO-3-N content in 10 cm soil layer was 1.6 times higher in RMridge that in 10 cm soil layer in RMfurrow，and 2 times higher in 10 cm soil layer in PNM.The highest maize yield was observed in the RM treatment (but not significant).The plant dry matter in RM and PM were increased by 36.15% and 16.11% than PNM，and nitrogen per plant were increased by 13.97% and 3.59%.It was concluded that the RM treatment could keep NO-3-N in the root zone(0~40 cm),reduce NO-3-N leaching.Therefore,the RM treatment (alternating ridges and furrow，the ridge mulched) was recommended for maize cultivation in dryland which was winwin for economy and environment.