Abstract: Due to the lack of electron donors in traditional constructed wetlands (CWs), the removal of \mathrmNO_3^- -N in the system is limited and N₂O emissions are exacerbated. To enhance the system's denitrification efficiency and reduce greenhouse gas (GHG) emissions, four types of enhanced CWs technologies have emerged recently: electrochemical enhancement, substrate modification, microbial augmentation, and plant enhancement. However, a systematic summary of these technologies is lacking. This review analyzes literature from the past five years to summarize the nitrogen removal efficiencies and mechanisms associated with these four types of enhanced CWs. It further examines the emission patterns and mitigation mechanisms of GHGs in CWs, and evaluates the efficacy and application potential of these systems for treating various types of wastewater. The results show that electrochemical enhancement technologies (such as MFC-CWs and MEC-CWs) improve the removal rate of TN by 4.81%-31.50%, especially at low C/N, by enhancing electron transfer efficiency. Substrate modification (such as adding biochar, pyrite, or manganese oxide) can raise the removal rate of \mathrmNO_3^- -N to more than 80% by providing adsorption sites or electron donors, but the saturation or consumption of filler may affect the stability in long-term operation. Plant enhancement optimizes the microbial environment through root oxygen release and secretion, which increases the \mathrmNH_4^+ -N removal rate by about 20%. Microbial enhancement is mainly used to mitigate the adverse effects of environmental stress on CWs. In terms of GHG emission reduction, enhanced technologies can reduce CH₄ emissions by 45%-93% and N₂O emissions by 27%-90%, by inhibiting methanogens, promoting methane oxidation or optimizing denitrification pathways. In the treatment of various types of wastewater, these technologies show considerable potential. For example, the addition of biomass carbon source can increase the removal rate of \mathrmNO_3^- -N to 98%, but may lead to an increase of GHG emissions. Limited by environmental conditions, the stability of enhanced technologies is difficult to maintain. Practical engineering applications still need optimization and validation. Future work should focus on multi-technology synergistic innovation and long-term stability research to achieve both nitrogen removal and carbon neutrality goals.