In order to study the influences of different durations of ozone aeration on the nitrogen content and form transformation in anaerobic sludge, the experiment was conducted with self-designed apparatus, with six different durations of ozone aeration, 0, 10, 20, 30,40, 50min, respectively, sampling and measuring content of nitrogen in different forms. The results showed that different durations of ozone aeration remarkably affected the nitrogen content in different forms in wastewater system. Specifically, the content of total nitrogen, Kjeldahl nitrogen, soluble Kjeldahl nitrogen, ammonium nitrogen, nitrite nitrogen, particulate organic nitrogen and particulate total nitrogen, showed significant decline trend with magnitudes of 124.76, 232.51, 11.45, 191.28, 4.35, 221.06 and 286.06mg/L （P<0.05), respectively. By the contrary, the content of soluble total nitrogen, nitrate nitrogen and dissolved organic nitrogen showed upward trend, which were increased by 161.29, 29.42 and 179.83mg/L at the end of 50min（P<0.05), respectively.