In order to explore the effect of different proportions of organic fertilizer instead of chemical fertilizer on soil ammonia volatilization，a field experiment was carried out in the rice-wheat rotation system of Chaohu lake basin using aeration method to replace chemical fertilizer with organic fertilizer from pig manure and straw. Six treatments were set up:no fertilizer(CK)，conventional fertilizer(CF)，pig manure organic fertilizer replace 50% fertilizer(CFP-50%)，pig manure organic fertilizer replace 30% fertilizer(CFP-30%)，straw organic fertilizer replace 50% fertilizer(CFS-50%)，straw organic fertilizer replace 30% fertilizer(CFS-30%). The test resulted showed that the peak of soil NH₃ volatilization occurred on the second day after fertilization in both rice and wheat seasons，and the cumulative emissions during the whole growth period were 3.72–22.15 and 1.35–12.68 kg·hm-2，respectively. The proportion of NH₃ volatilization in the whole growth period of base fertilizer stage was 56.34%–62.86% and 50.32%–52.29%，respectively，which was the NH₃ volatilization concentration period. Compared with CF treatment，the average NH₃ volatilization rate and cumulative emissions of soil treated with pig manure organic fertilizer and straw organic fertilizer instead of chemical fertilizer were significantly decreased(P<0.05)，and the decreases ranged from 19.90% to 53.60% and 20.66% to 53.54%，respectively. Among them，the single-season cumulative NH₃ emissions of CFS-30% treatment in rice season and CFP-30% treatment in wheat season were significantly reduced compared with CF treatment，with a decrease of 53.54% and 51.08%，respectively，while the annual cumulative NH₃ emissions of CFS-30% treatment was reduced by 44.71% compared with CF treatment.At the same time，NH₃ emission and NH₃ emission coefficient of soil unit yield of pig manure and straw organic fertilizer were significantly lower than those of CF treatment(P<0.05)，and the decrease was as high as 59.59% and 64.34%，respectively. Correlation analysis showed that the NH₃ volatilization rate of soil under fertilization treatment had a significant negative correlation with soil mass water content，a significant positive correlation with ammonium nitrogen and nitrate nitrogen contents of soil and surface water(P<0.01)，and a significant positive correlation with wheat season temperature(P<0.05). To sum up，the substitution of straw organic fertilizer for 30% chemical fertilizer in the Chaohu lake basin resulted in the minimum soil ammonia volatilization during the rice-growing season，while pig manure organic fertilizer substitution for 30% chemical fertilizer showed a more significant effect in reducing soil ammonia volatilization during the wheat-growing season，but considering the annual rice-wheat rotation as a whole，straw organic fertilizer substitution for 30% chemical fertilizer achieved the best effect in reducing soil ammonia volatilization.