Abstract: In order to mitigate the membrane fouling problem in the present heavy oil wastewater treatment process, wastewater quality and membrane foulants were analyzed to determine that organic fouling was the main fouling mechanism. According to the characteristics of the heavy oil wastewater pollutants, high efficient degrading bacteria were screened by the restrictive cultivate technology. The strain was identified to be pseudomonas and bacillus. Then biological treatment unit was added in the existing process and simulation process was established. The results of long-term running experiments showed that the oil content and COD could be decreased from 11-20 mg/L and 216 -350 mg/L to 0.6-1.1 mg/L and 53-88 mg/L respectively. Therefore organic pollutants in the heavy oil wastewater were degraded effectively by biological treatment. Besides, the membrane flux loss was below 15%.The microscopic observation of membrane surface also showed that membrane fouling was inhibited effectively.