Abstract: The demulsifier screening was conducted for Northen Xinjiang high acid super heavy crude oil and the deacidification coupled with desalting pretreatment with it were studied. The influence factors on the deacidification and the desalting were investigated. Experimental results show that SXF2040 demulsifier is better for Northen Xinjiang crude oil. The optimal conditions for the deacidification of Northen Xinjiang crude are 70 ℃，400 r/min, reaction time 3 min, demulsifier to crude ratio 0.3, and settling time 30 min. At these optimal conditions, the deacidification rate reaches 94.6%. The acid number of the treated crude is 0.23 mgKOH/g, meeting the standard of low acid crude oil. While at the following conditions: SXF2040 demulsifier dosage of 20 μg/g, 130 ℃，water injection rate of 10%，combined electric strength of 400，-800，-1 200 V/cm and the corresponding processing time of 12 min, 10 min and 8 min，respectively, after deacidification-desalination two stage pretreatment, the acid number of the crude reaches a low acid value of 0.08 mgKOH/g, salt content less than 3 mg /L and the content of sodium is reduced to 1.75 μg/g.