Abstract: The oil industry is a high contaminative business.Because of the unreasonable discharging sewage and the running,dripping,leaking in production process,a large amount of poisonous harmful organic pollution enter the groundwater system,and cause the water quality of groundwater to worsen,the groundwater environment to degrade,even restrict the development of the industry and agriculture,endanger the people being's health.The petroleum pollution has already become the serious environmental problem.A case study from an oil industry area presented by this paper concerning the survey of the petroleum pollution to groundwater,from that the paper researched and summarized characteristic of petroleum pollution,space distribution regularities of pollution source,mechanism of petroleum pollution to groundwater.