The effects of straw mulching on red soil N mineralization at different temperature,soil moisture,N fertilization were investigated through laboratory aerobic incubation.The results showed that if the soil was mulched by straw,its net N mineralization was lower than that of the non-mulched soil during the incubation time at 20，30℃.At 40℃ the net N mineralization of soil in mulching was lower than that of non-mulching during the first 40-day but higher than that of non-mulching after incubating 60 days.When the soil moisture was at 0.20 cm3/cm3 or 0.25 cm3/cm3,the difference between the mulching and non-mulching was more remarkable than that at 0.15 cm3/cm3.When the temperature was raised,the difference was narrowed and even disappeared.The straw mulching also had effects on soil N nitrification and N ammonification.When the temperature was 20℃ and soil moisture was 0.15 cm3/cm3,N nitrification was lower and N ammonification was higher in the mulching treatment.When the temperature was 40℃ and soil moisture was 0.25 cm3/cm3,N nitrification was higher and N ammonification was lower in mulching treatment than that of non-mulching treatment.These results suggest that it is essential to adjust the application of straw mulching in red soil fields according to the soil moisture and N fertility.