Abstract: To assess the influence of the Shengli Oilfield oil exploitation on surface water, water samples were collected from 18 locations in the major rivers of Dongying City. Medaka (Oryzias latipes) feeding and egg hatching experiments were conducted to assess the acute and chronic toxicity effects of the water bodies in the laboratory. The results showed that medaka juvenile fish did not have acute toxicity in the 18 samples from the Shengli Oilfield. However, the hatchability of medaka was influenced in 88.9% of the samples, reaching an extremely significant level (P<0.05) in 72.2% of the samples. It was also found that there was no significant correlation (P>0.05) between the object of chronic toxic effects and nine observation indices of the water bodies. The results suggested that the protocol of using medaka to evaluate the Shengli Oilfield water toxic effects was feasible. Medaka was influenced to a certain extent by the chronic toxicity of the water bodies. Furthermore, no regularity was found between water pollution locations and spatial distribution of oil wells in the Shengli Oilfield area.