Abstract: Low-pollution water has the characteristics of wide sources, large water volume, strong fluctuation of water quality and quantity, and relatively low concentration of pollutants. Constructed wetland is an effective measure to treat low-polluting water. In this paper, the oxygen increasing mechanisms of two typical oxygen-enhanced constructed wetlands, i.e. tidal flow constructed wetlands and aerated constructed wetlands, for nitrogen removal from low pollution water were described, and their denitrification effects and the influencing factors were analyzed. The results show that in the tidal flow constructed wetland, proper idle time and submerged reaction time can create good aerobic-anaerobic conditions, which is beneficial to the removal of TN; when the operating cycle to be less than 24h, and the submerged ~idle time ratio to be between 0.25-4 and 0.5-7, the wetland would have the best NH₃-N and TN removal effect in low-polluted water. Reasonable aeration can make the constructed wetland to maintain a high pollutant removal rate at low temperature (-5-10℃); for the treatment of low-polluted water by aeration constructed wetland, the best air-water ratio is 6:1, and the best aeration part is the bottom of the wetland. In addition, by comparing the denitrification effects of the two constructed wetlands, it shows that the treatment effect of aerated constructed wetlands on the removal of NH₃-N and TN was better than that of the tidal flow constructed wetlands, but the treatment effect of COD removal was weaker than that of tidal flow constructed wetlands. Finally, this article also points out the existing problems in the denitrification of low-polluted water in the two constructed wetlands. The results of this study could be used as a reference for similar further researches.