Field experiments were carried out to identity the optimum uncovering plastics film period and nitrogen amount for higher yield and better growth index of spring maize under the plasticcovered ridge and furrow planting in Loess Plateau of East Gansu.Three uncovering plastics film periods(uncovering plastics film at jointing stage,uncovering plastics film at teaseling stage and mulching plastics film for whole growth stage)and three nitrogen amount(N 0,150,225 kg/hm2）were applied to study the interaction between uncovering plastics film period and nitrogen amount on growth and yield of spring maize.The results showed that the effects of uncovering period or applied amount of nitrogen on the yield reached significant or extremely significant difference,while their interaction was not significant.The yield and water use efficiency of uncovering plastics film of teaseling stage were the best among all the treatments.There was no significant for the yield of spring maize between the treatments of uncovering plastics film at jointing stage and mulching plastics film of whole growth stage.The spring maize yield was extremely significant higher for applying nitrogen(high or low nitrogen)treatments than those of no nitrogen fertilizer treatments,and yield increased with the increasing of nitrogen application amount.Compared with low nitrogen treatment,the yield was increased in a certain degree for applying high nitrogen treatments,but the difference was not significant.The maize leaf SPAD value,photosynthetic rate and leaf area index were much better with higher nitrogen and uncovering plastics film of teaseling stage.Considering yield,water use efficiency and growth index,uncovering plastics film of teaseling stage combined with nitrogen application amount of 150~225 kg/hm2 was a most suitable cultivation mode under Ridge and Furrow Planting in Loess Plateau of East Gansu.