Film mulching and nitrogen fertilization are two effective practices to promote maize production in northwest China, but their impacts on environment in terms of greenhouse gas emission remain unclear. Two-year field trials were conducted to 1) explore the effect of the film mulching pattern and N fertilization rate on maize production, gaseous N emission, and utilization of N and water; 2) find an optimal mulching pattern and N-fertilization rate to achieve green development. Trial Ⅰ included flat planting with non-mulching (NM), ridge-furrow with plastic film mulch (PM), ridge-furrow with biodegradable film mulch (BM), and flat planting with full plastic film mulching (FM). Trial Ⅱ involved BM with N-fertilization rates (0, 90, 180, and 270 kg N ha⁻¹), denoted as BMN0, BMN1, BMN2, and BMN3, respectively. The results showed that film mulching significantly decreased the daily flux and cumulative flux of gaseous N by an average of 32.02%, 35.17% (NH₃), 78.70%, 75.83% (N₂O), respectively, as compared with NM. Film mulching also significantly increased the amount of soil residual mineral N after harvest, plant N uptake, and soil water storage but decreased evapotranspiration by an average of 8.31%, 9.42%, 17.45%, and 25.34%, respectively, as compared with NM. In addition, grain yield, water use efficiency (WUE), N uptake efficiency (UPE) (except for BM), N harvest index (NHI), N use efficiency (NUE), and partial productivity of N (PNP) were significantly higher in the mulching treatments, and yield–scaled NH₃ emission (YSN) was significantly lower in PM and BM, as compared with NM. Compared with FM, soil residual mineral N after harvest, plant N uptake, grain yield, WUE, NUE, and PNP were significantly lower but NHI was significantly higher in PM and BM. The daily flux and cumulative flux of N₂O emission and the amount of soil residual NO₃⁻ -N after harvest were significantly lower but plant N uptake was significantly higher in PM than in BM. Collectively, BM was the best mulching treatment in this study. With increase of N-fertilization rate, the daily flux and cumulative flux of NH₃ volatilization, the peak period, and the cumulative flux of N₂O emission, the grain yield, WUE, NUE (except for N3), and YSN were significantly increased but NHI, PNP, and UPE were significantly decreased. The optimum N-fertilization rate under BM was found at 173 kg ha⁻¹, which could achieve the goal of high yield, efficient utilization of water and nitrogen, and environmental friendliness.