In this study, the characteristics of nitrogen transformation in tea garden soil of Shandong Province were analyzed by indoor aerobic culture. Soil N transformation and enzymes activities in constant wet and dry/wet cycle conditions were measured. The results showed that: (1) The net mineralization quantity and net nitrification quantity, the activities of urease and nitrite reductase were the highest in the 60%WHC treatment at the end of incubation. The net mineralization and net nitrification rates were seriously inhibited in 20%WHC treatment. (2) In dry/wet cycle treatment, net mineralization quantity, net nitrification quantity and enzymes activities increased and the change of "pulse" pattern appeared. (3) N₂O emission was greater than NH₃ volatilization in both models. N₂O emission was directly proportional to soil water content, while NH₃ volatilization was inversely proportional. Dry wet alternation enhanced N₂O and NH₃ emissions. (4) The structural equation model revealed that soil water content affected soil N transformation (p<0.001); urease significantly improved soil N transformation in constant wet treatment (p<0.001), while nitrate reductase inhibited N transformation (p<0.001) in constant wet and dry/wet cycle models. These results might help to better regulate soil management and the use of N fertilizer in the tea garden ecosystem under different water supply conditions.