Functional genes related to soil nitrogen (N) cycling are widely involved in a series of ecological processes, including N fixation, ammonification, nitrification and denitrification, and are key components of the N biogeochemical cycling, which greatly affects soil productivity, carbon neutralization, and agricultural sustainable development, as well as global environmental changes. In recent decades, the rapid development of molecular and microecology technology has promoted the research about functional genes related to soil N cycle and their microbial functional communities. In order to objectively and analyze the research trends, hotspots, and historical trends in the field of functional genes related to soil N turnover, the pertinent literature retrieved from the Web of Science database from 2001 to 2020 was analyzed from four aspects of publications amount, highly cited papers, high-frequency keywords and historical direct citations based on knowledge mapping. The results showed that: 1) The application of molecular biology techniques to excavate the functional genes and community structure related to soil N turnover so as to explore the microbiological mechanism is the current hotspot and entry point in the research field. 2) The research about soil N turnover functional genes mainly focused on three aspects: (1) Using metagenomics and other technologies to screen, identify and annotate the functional genes related to soil N turnover, so as to discover new microbial functional gene sequences and updates primer database, etc.; (2) Effects of environmental factors and agricultural management practices on soil N turnover related microbial indicators; (3) Using functional gene abundance to characterize the soil N cycling processes-related functional microorganisms, as well as analyze the relationship between functional genes, soil properties, and microbial community structure, in order to reveal the molecular mechanism of soil nitrogen turnover. 3) The historical development context of soil N turnover functional genes was from the screening, identification, identification, corresponding primer design and analysis method determination of N-cycling functional genes, to the influencing factors (or environmental conditions) of soil N turnover functional genes, combined with the current data of the activity, abundance of functional genes related to soil N turnover, and functional microbial populations, community structure and even soil properties, to comprehensively explore the microbial mechanism of soil N cycling.