Abstract: Straw returning is one of the important approaches in improving the nitrogen efficiency of crops. Nitrogen efficiency is affected by environment conditions and field management. However, most studies were conducted in specific region or environment, systematic comparison and analysis of straw returning on nitrogen use efficiency in different regions of China was less. This study conducted a meta-analysis based on data from 77 peer-reviewed publications to determine the response of nitrogen use efficiency of major grain crops in Chinese farmland to straw return and its key regulatory factors. The results showed that compared to non-straw return, the straw return increased the effect size of NUE (nitrogen fertilizer use efficiency) and PFP_N (nitrogen partial factor productivity) by 10.0% and 6.14% (P < 0.05). The returning method was the key regulatory factor for the effect of straw returning on NUE, in which the increase of NUE in mulching returning was about 2 times than that in burying returning. The key factors affecting the regulation of PFP_N by straw returning were soil total nitrogen, soil acid-base and climate type. When soil total nitrogen content was more than 1.25 g·kg⁻¹ or under neutral soil conditions, the increase of PFP_N was significantly higher than other levels with this factor. Under subtropical monsoon climate and temperate monsoon climate, straw returning had significant effect on PFP_N enhancement. Regression analysis showed that the effect of straw returning on PFP_N increased with the increase of soil total nitrogen content (P < 0.05), and increased first and then decreased with the increase of soil pH. The average annual temperatures and rainfall were found to be nonlinear correlated with PFP_N (P < 0.0001). In conclusion, straw returning would significantly increase the nitrogen fertilizer utilization rate of major grain crops in China, while there were significant differences in the response degree of different indexes to straw returning and its key regulatory factors.