The geological environment in karst area is vulnerable, especially in the shallowly buried karst region, the groundwater there is easily to be polluted. The characteristics of groundwater gasoline pollutants migration is analyzed by studying instance of petrol leakage at a gas station 10 years ago in Guiyang City in this paper. The results are as follows: 1) influenced by the lithology, construction, thickness of aeration zone, heterogeneous characters, the gasoline pollutants migrate mainly through karst tube, bedrock surface, fracture, and cracked top strata of the bedrock; 2) the gasoline pollutants migrate and diffuse preferentially through fault, fracture, karst cave, and lateral migration is stronger than the vertical one; 3) other than migrate with groundwater flow, organic pollutants also disperse apparently in those bedrock uplifted part and high topography part; 4) as red clay has high sorption to pollutants, pollutants mainly contaminate the nearby bedrock, only very few can contaminate the upper part; and 5) the gasoline pollutants are buried in karst tube, karst fracture and ect.