Abstract: The 1.5 m3/h crude from 2Mt/a No.2 atmospheric and vacuum distillation unit in Karamay petrochemical co. was fed into in a self-made small scale electric desalting device for decalcification test with own developed complexing decalcifying agent. The results show that for low calcium content crude oil, 6% water injection and dosage of decalcifying agent 60ppm, using a structured channel mixer followed by tube packing mixer, can get the removal rate of Ca, Fe and Mg of 71.5%～78.2%，32.3%～45.5% and 30.0%～38.2%，respectively. The water content in decalcified oil is less than 0.3%. The discharged water meets the quality requirements for industrial use.