Soil nitrogen transformation processes，such as organic nitrogen mineralization，adsorption-desorption of ammonium nitrogen by clay minerals，immobilization-release of nitrogen by microorganisms，and nitrification-denitrification，collectively determine soil nitrogen retention and supply capacity as well as crop nitrogen use efficiency. However，long-term intensive cultivation and the “excessive utilization with inadequate maintenance” planting pattern have led to severe soil degradation，which reduces soil nitrogen retention and supply capacity，decreases nitrogen use efficiency，and triggers environmental risks. Meanwhile，the inadequacies in research methods for soil nitrogen turnover processes have also restricted our quantitative analysis of key nitrogen transformation processes. Therefore，based on a systematic elaboration of soil nitrogen turnover，this paper reviewed the mechanisms by which different nitrogen management strategies，including deep placement fertilization，slow/controlled-release fertilizers，and the use of inhibitors-improve nitrogen fertilizer use efficiency，as well as how organic materials with different properties regulate soil nitrogen retention and supply capacity. It also summarized cutting-edge research methods for soil nitrogen cycling world wide. The aim was to provide theoretical support and technical guidance for improving soil fertility and efficient nitrogen utilization，thereby facilitating the realization of green and sustainable agriculture.