Abstract: In the actual transportation of products pipeline, the batch of diesel-gasoline batch transportation is usually cut according to the fixed proportion, but there is still a long section of contaminated oil after the second cutting in some pipelines. In this paper, laboratory blending experiment and site test for contaminated oil cut into tanks were carried out on the contaminated oil in the pipeline where 93^# gasoline driven by 0^# diesel of 65 ℃. After the second cutting of contaminated oil, the trailing oil product was cut into the empty tank, the clean diesel tank with consistent flash point and the clean tank containing the diesel of different flash points, respectively. Then, the calculation and analysis were conducted correspondingly to obtain the volume the moment the oil product in the tank is qualified. It is indicated that the oil is qualified when the volume in the tank is 600 m³ if the trailing oil product is cut into the empty tank. If it is cut into the clean diesel tank in which the flash point is the same and the volume of the stored oil is 50 m³ and 100 m³, the oil product is qualified when the volume in the tank reaches 530 m³ and 450 m³, respectively. If it is cut into the clean diesel tank with the stored oil of 60 ℃, the cutting volume is greater. And if the stored oil is 70 ℃, the cutting volume is smaller. The research results can be used as the guidance for the cutting of contaminated oil.