Located on the Yellow River Delta,Shengli oilfield is the second biggest oilfield in China.A great quantity of crude oil drops on the surface in the oil exploitation.Under, the erosion of rainfall, the oil pollutants on the surface arc removed and entered into water area by the surface runoff.As a reault, it makes severe damages to water environment,including river,shallow sea.So,runoff coming from every land owd is regarded as nonpoint sources of oil pollution to water environment.According to the origination and development of nonpoint source pollution,nonpoint sources of oil pollution to water environment in the experimental study region are classified into thirteen categories.The erosion of oil are related to the runoff volume,oil loadings,and the distr ibution area of nonpoint sources.The first one related to the precipitation and the value of CNwhich mainly depend on the hydrographic types (four types are classified in the experimental study region).The second one can be obtained from the results of samples analysis, the third one can be measured from the land use map.Applying the results of experimental study to the whole Yellow River Delta,the annual eroston of oil in the whole Yellow River Delta is calculated.The contribution of nonpoint sources to the oil volume of entering marine in Yellow River Delta is 11.58%.