Abstract: The major nitrogen transformation pathways in constructed wetlands include nitrification and denitrification of microbe, plant uptake and adsorption by substrate. As an important aspect of hydrological processes, water-level change can directly or indirectly affect the quality and quantity of nitrogen in various forms. The nitrogen transformation mechanism and influence factors of constructed wetlands were expounded, and the relevant research achievements of the wetland plants' morphological characteristics and growth, the physical and chemical properties (DO, pH, Eh), and the intensity of microorganism nitrification and denitrification in response to water-level changes in wetland were summarized. The problems existing in previous studies were pointed out and some suggestions put forward, including strengthening researches on the influence of different water-level change modes (such as change range and period) on nitrogen transformation in various forms in the constructed wetlands, and increasing the nitrogen removal effect through improving plant growth and enhancing the intensity of microorganism nitrification and denitrification with water level control.