Accidentally spilled oil can cause great harm to the ecological balance of water once it enters the environmental waters. Clarifying its movement behavior and migration law in water has been the focus of environmental hydraulics research. This review starts from the mechanism of the oil spill migration process, and firstly reviews the kinematic characteristics of the smallest moving unit of the oil spill, the individual oil droplet, as well as focusing on several key aspects such as droplet shape, trajectory, terminal velocity and drag coefficient. Subsequently, considering the commonalities and differences between inland riverine and oceanic environments, different aspects of oil droplet collision, coalescence, breakage, particle size distribution, and vertical diffusion are discussed separately. Finally, the current status of research on the migration laws of accidental oil spills in environmental waters is summarized, and feasible future research directions are proposed to address the emerging research problems and research gaps.