Light significantly shapes microbial metabolism and their interactions with environments and other organisms, and thereby affecting microbial community compositions and diversity in different ecosystems. The pollution of light in urban areas would increase with urban intensification and adversely influence biological entities. Though light is essential for certain microorganisms, artificial light at night (ALAN) disrupts natural circadian rhythms and profoundly alters microbial behaviors and ecological balances through various pathways, ultimately reshaping microbial communities and functions in urban ecosystems. Such disruptions may trigger cascading consequences for urban ecosystem health and functionality, posing threats to human beings. This review focused on ALAN pollution in urban areas, systematically elucidating its impacts on microbial dynamics across diverse urban habitats such as soil, water, and air. Additionally, this paper investigated the changes of microbial ecosystem functions and potential health risks associated with ALAN, and discussed the application of ALAN in ecological restoration. At last, this review prospected the important research fields about ALAN, including the mechanism of ALAN impacts on urban microbiome and their functions, and the influences of ALAN on human health. The review would offer theoretical basis for city light planning, improvement of environmental quality, and ensuring human health.