Abstract: Per- and polyfluoroalkyl substances (PFAS) precursors are indirect sources of many PFAS in the environment, widely utilized in various fields such as food packaging, firefighting foams, metal plating, textile coatings, and pesticides. Due to the transformation of PFAS precursors in the environment and limitations in analytical testing methods, PFAS precursors are often neglected. The biological toxicity of PFAS precursors has been confirmed, including their interference with normal fetal development, induction of immunotoxicity, and cell apoptosis in the mother's body. Moreover, PFAS precursors can transform into stable PFAS, posing sustained hazards to the ecological environment and biological health. Investigating the transport and transformation behavior of PFAS precursors in different environmental media is crucial to their contaminant control. Based on recent researches, this study provides a comprehensive review of the major sources and existence characteristics of PFAS precursors, as well as their transport and transformation behaviors in environmental media such as the atmosphere, soil, and water bodies. The results indicate that PFAS precursors have been widely detected in water bodies, soils, suspended particulate matter (SPM), sediments, and the atmosphere worldwide. During the transport process, water bodies are the main carriers of PFAS precursors, while soils, SPM, and sediments mainly play a role in retention. In addition, long-distance transport through the atmosphere is an important source of pollution in extreme areas. Furthermore, the retention and migration of PFAS precursors in environmental media often accompany transformation, resulting in producing PFAS that endangers the ecological environment and biological health continuously. This article reviews the research progress on the migration and transformation of PFAS precursors in the environment, aiming to provide the basis for the pollution prevention and control of PFAS precursors and PFAS.