Plastic film mulches are commonly used to improve soil hydrothermal conditions to increase crop yields. However, it remains uncertain how different plastic film mulching influence greenhouse gas (GHG) emissions. Field experiments were conducted with drip-irrigated potatoes under no mulch (NM), transparent plastic film (TM) and black plastic film (BM) in an arid area of Northwest China from 2021 to 2023. Their impacts on GHG fluxes and related drivers, as well as the effects on potato productivity, global warming potential (GWP), and greenhouse gas intensity (GHGI) were investigated. Results revealed that two plastic film mulches had different effects on surface GHG emissions. Compared with NM, TM significantly reduced surface methane (CH4) uptake by 7.2 %-12.7 % and increased surface nitrous oxide (N2O) emission by 12.7 %-16.2 %. BM maintained CH4 uptake levels similar to NM but elevated N2O emissions by 10.4 %. Both films altered gas diffusion within the soil profile. In the 0-20 cm soil layer, TM and BM significantly reduced cumulative CH4 diffusion by 14.5 % and 10.1 %, respectively, while increasing cumulative N2O diffusion by 6.8 % and 5.9 %, respectively. The reduction in CH4 diffusion was more significant in the 20-40 cm soil layer. Water-filled pore space (WFPS) had the greatest relative importance for CH4 and N2O fluxes under NM, while soil NO3 --N was the most important factor for TM and BM. Plastic film mulching had a negative effect on CH4 downward diffusion and a positive effect on N2O upward diffusion, with WFPS and NO3--N being the more important influencing factors, respectively. TM exhibited the highest GWP and GHGI, while no significant difference in GHGI was observed between BM and NM. BM resulted in higher average tuber yield and plant carbon uptake. In conclusion, it is recommended to adopt black plastic film for potato production in Northwest China based on productivity and GHG emissions.