Long-term exposure of food crops to high concentrations of ambient ozone (O₃) can cause significant yield reductions. O₃-induced crop loss studies are limited in China, especially in the North China Plain (NCP) where agricultural resources are abundant and O₃ concentrations are high. In this study, we quantify the O₃-induced adverse impacts on wheat and maize over the NCP and Shanxi province during 2013-2018 through the use of high-resolution air quality reanalysis dataset and land-use dataset. Results show that the accumulated hourly O₃ concentration above 40 ppb (AOT40) in croplands experienced an upward trend, with an annual increase of 2.2 ppm h (18.1%) during the wheat growing period and 1.5 ppm h (10.9%) during the maize growing period from 2013 to 2018. O₃-induced relative yield losses grew from 17.9% in 2013 to 38.6% in 2018 for wheat, and ranged from 7.5-11.9% for maize. The estimated crop production losses also increased over time. Shandong and Hebei provinces are the hot spots of crop losses and priorities should be given to them for O₃ pollution prevention. Comparison with previous studies shows that uncertainties still exist in crop loss estimations. More rural O₃ measurements and localized crop exposure-response experiments should be performed for better assessments.