Nine experiments were carried out on 39 healthy male adults for a total of 54 decompressions from N2-O2 saturation diving at the denths of 20-50 m. Excess supersaturation pressures of nitrogen dissolved in 1200 min tissue were calculated at all depths in decompression. In Exp. Ⅷ when chamber pressure was decompressed from 50 m to 35 m, a slight decompression sickness occurred, while ΔP1200 reached 7.05 m. Based on the above-mentioned analysis and calculation, the stage decompression schedules of N2-O2 saturation exposure at 36.5 m were revised.