An anaerobic incubation was conducted to investigate the effect of urea combined with pig manure and cattle manure at different ratios on characteristics of NH+4 releasing in a paddy soil collected from Nanchang,Jiangxi province.Our results indicated that urea(U)combined with pig manure(P)or cattle manure(C)(except for 80%U+20%C,70%U+30%C and 50%U+30%C treatments) significantly decreased soil cumulative NH+4 released by 5.78% to41.20% at day 28 of anaerobic incubation as compared with 100%U treatment (P<0.05);Thereafter in the following 28~90 days,the amount of soil NH+4 released increased significantly in manure treatments except for 50%U+30%C treatment.Compared with 100%U treatment,50%U+50%P and 80%U+20%C treatments significantly the cumulative NH+4 released were increased by 4.81% and 9.32%,respectively (P<0.05) at the end of the incubation experiment,but showed no significant difference with other treatments.There was no significant difference in the cumulative NH+4 between 100%U treatment and 80%U,50%U+30%P and 50%U+30%C treatments.It was suggested that 50%U+30%P had the potential to reduce the risk of N lose and supply the N demand of crops in paddy soil.