When crude oil is dehydrated with conventional demulsifiers, the dehydration rate is low which cannot meet the existing treatment requirements. To solve this problem, in this paper, a non-polyether demulsifier (St-BA-AA) was synthesized with styrene (St), butyl acrylate (BA), and acrylic acid (AA) as monomers, vinyl triethoxy silane as modifier by emulsion polymerization, which was compounded with the conventional demulsifier (PAMAM). The influence of temperature, setting time, compound ratio, HLB, IFT of two different demulsifiers was investigated in detail. The HLB measurement indicated that the closer the proportion value of HLB to the crude oil, emulsifiers have a better ability of replacing natural emulsifiers. The IFT measurement showed that when the dosage of demulsifier was 100 mg/L, the oil/water interfacial tension reached its lowest point. By optimizing the operating condition, more than 99.6% (wt) water was removed from the crude oil.