Abstract: Groundwater systems in karst areas are highly vulnerable to rapid contamination by industrial pollutants due to their complex fracture networks and high permeability, making the treatment of oil-containing wastewater particularly challenging. This study investigates an oil-containing wastewater overflow incident at a coal coking company in Panzhou City, Guizhou Province. By integrating hydrogeological surveys, geophysical exploration, tracer tests, and stratified sampling techniques, this paper revealed the migration mechanisms and distribution characteristics of pollutants in the karst fracture zone. The results show that pollutants rapidly migrate horizontally along NE-NW trending “X”-shaped joints, following a pathway from the leakage area → CK4 borehole near the factory gate → CK3 borehole in the southwest of the factory → S001 spring outlet. Vertical contamination is limited to shallow groundwater (＜130 m), with a polluted area of 0.73 km², a maximum pollution index of 96.8, and a self-purification capacity of 20.97 mg·L⁻¹·d⁻¹. Residual petroleum hydrocarbons in the vadose zone constrain natural attenuation efficiency, but artificial water injection significantly accelerates pollutant removal. Based on migration characteristics and remediation potential, the authors propose a comprehensive treatment strategy of “separation of clean and polluted water, curtain interception, and dynamic monitoring”. By intercepting upstream clean groundwater and constructing pollution barriers, this approach effectively curbs contamination spread, reduces treatment costs, and improves efficiency. The findings provide a scientific basis for preventing and controlling oil-containing wastewater pollution in karst groundwater systems in southwestern China.