In order to meet the demand for demulsification and cost of oilfield chemicals in Xinjiang oilfields and reduce the environmental pollution，this article based on the environmental safety and the complex situation of shale oil fracturing produced fluids in Madong block of Xinjiang. Ten kinds of biodemulsifiers synthesized by microbial fermentation were screened and the evaluated by the bottle test method. The demulsification of the fermentation broth and the purified extract was compared. Meantime，the compound demulsification effect of biological demulsifier and conventional chemical demulsifier was studied，and then the process of demulsification was optimized. The results showed that the biodemulsifier XJ-4-2 synthesized by XJ-4 bacteria had good compatibility with the extracted fluid from Madong block. The dehydration rate was more than 80%. Under the condition of 60 ℃ and 120 min demulsification time，the dehydration rate of the compound system containing biological demulsifier XJ-4-2 and chemical polyether demulsifier reached near 95%. Under the condition of 50 ℃，200 mg/L dosage and 2 h thermochemical sedimentation，the water content of remaining crude oil and oil content of sewage were decreased. The biological demulsifier had high dehydration rate and low oil content in sewage at low temperature，which improved the problem of rapid low-temperature dehydration of shale oil fracturing produced fluids in Madong block.