Improving nitrogen use efficiency (NUE) is crucial for sustainable agriculture. Despite recent advancements, China continues to face significant environmental risks due to nitrogen surplus. This study examines the spatiotemporal dynamics of cropland nitrogen use across 350 prefecture-level cities from 1980 to 2020. Results reveal a persistent “three highs and one low” pattern-high input, high output, high surplus, and low NUE. Although NUE increased from 35 % in 2003 to 49 % in 2020, the turning point occurred around 2005, coinciding with the national fertilizer reduction policy. Significant regional disparities remain, with low NUE in the Northwest and Qinghai-Tibet Plateau and high NUE in the Northeast and Sichuan Basin. A temporal lag between nitrogen input and NUE highlights the legacy effects of past nitrogen accumulation. Practices such as straw return and manure recycling in key regions have demonstrated benefits. Findings underscore the need for region-specific, resource-efficient nitrogen governance strategies to enhance long-term sustainability.