Black plastic film mulching is a common practice for potato production in the arid area of Northwest China. Many studies have reported the significant positive effect of black plastic film mulch on potato harvest, while the effect of black plastic film mulch treatment on soil nitrous oxide (N2O) emissions is still unclear. As a consequence, this study aimed to examine the effect of black plastic film mulch treatment on N2O emission from arid upland potato fields. With the static chamber-gas chromatography method, soil N2O emissions were measured. The results showed that black plastic film mulching treatment significantly increased cumulative soil N2O emissions by 21-26% compared with non-mulched treatment. Cumulative N2O emission positively correlated with soil temperature, soil moisture, soil CO2 concentration, and amoA-AOB abundance. This study indicated that black plastic film mulching, mainly through increasing soil temperature and soil moisture, increasing soil carbon dioxide (CO2) concentration, and promoting the abundance of nitrification-related functional gene of amoA-AOB, regulated N2O emissions. This study also highlighted that the specific soil environment under black plastic film mulch is conducive to N2O emissions and lay the foundation for settling the contradiction between food production and greenhouse gas mitigation in upland soils. The negative effects of black plastic film mulching on the environment should be considered in future applications in food production.