Soil freeze-thaw cycles (FTCs) during the non-growing season influence soil respiration (Rs), yet the effect of widely used plastic film mulch (PFM) on FTCs remains unclear. Based on four years of high-frequency observations in the semi-arid Loess Plateau, we found that PFM shortened the freeze-thaw transition (F-T) period by 59 days per year and extended the freezing period by 42 days per year through reducing the daily soil temperature (ST) range by 2.5 degrees C during the non-growing season. Although microbial biomass carbon (MBC) decreased during the F-T period compared to the freeze period, increases in dissolved organic carbon (DOC) and the activities of beta-glucosidase (BG), cellobiohydrolase (CBH) contributed to higher Rs under both treatments. PFM did not significantly influence Rs (relative to the control) within either period. PFM increased cumulative CO2 emissions by 24 g C m- 2 due to the extended freezing period, while reducing emissions by 47 g C m-2 owing to the shortened F-T period. PFM increased Rs by 24 % during the thaw period, causing only an 8 g C m- 2 rise. Overall, PFM reduced cumulative CO2 emissions by 16 %. To investigate the regional effect of PFM on FTCs, we used a process-based model with good performance to simulate the spatiotemporal patterns of FTCs in PFMapplied cropland across northern China. Simulations showed that PFM shorten annual F-T periods by approximately 15 days, especially between 35 degrees N and 45 degrees N. Of the un-mulched cropland in northern China, 7 % showed an increasing F-T duration from 1990 to 2019, a figure which potentially increased to 11 % under PFM, mainly located in Northeast China. During the same period, 16 % of the un-mulched cropland showed a decreasing F-T events, which increase to 19 % under PFM, primarily in the central part of northern China. These results suggest that PFM effectively reduces F-T duration and may mitigate non-growing season Rs.