A 11-year experiment was conducted in 2010 in order to evaluate the effects of long-term continuous straw incorporation and biochar application in wheat season on N₂O emission from a paddy field under rice-wheat rotation system, in which five treatments were setup: no maize straw incorporation and biochar application (CK); 6 t/(hm²·a) maize straw incorporation (CS); 2.4 t/(hm²·a) biochar application (BC1); 6 t/(hm²·a) biochar application (BC2) and 12 t/(hm²·a) biochar application (BC3). The results showed that BC2 and BC3 significantly improved soil properties such as alkaline hydrolysis nitrogen (AN), available phosphorus (AP), available potassium (AK), readily oxidizable carbon (ROC), dissolvable organic nitrogen (DON) and soil microbial biomass nitrogen (SMBN). CS, BC1 and BC2 had no significant effect on seasonal cumulative N₂O emission from paddy soil, while seasonal cumulative N₂O emission increased by 245.31% under BC3 compared to CK. Seasonal cumulative N₂O-N emission and the peak period cumulative emission after nitrogen application of BC3 were increased by 3.84 kg/hm² and 3.36 kg/hm², respectively, compared to CK. The promoting effect of BC3 on soil N₂O emission was mainly in the peak period of N₂O emission after nitrogen fertilizer application. Compared to CK, BC3 significantly increased soil cation exchange capacity (CEC), microbial biomass carbon (SMBC) and SMBN by 20.35%, 26.13% and 49.96%, respectively. Cumulative emissions at the peak period of N₂O emissions caused by re-flooding and panicle fertilizer application accounted for 27.66% - 32.83% of seasonal cumulative emissions, of which BC3 having the highest proportion. In conclusion, long-term continuous application of biochar can increase soil CEC and the retention of soil NH+ 4, thus can promote soil nitrification process, and interval prolongation between panicle fertilizer and re-flooding may effectively reduce N₂O emission from paddy fields.