Most crude oil and petroleum wastewater produced from oil fields are usually in the form of emulsions, which makes their demulsification a high challenging process. Usually, chemical demulsifiers are used to increase the efficiency of demulsification. However, there is still an urgent need to develop more efficient processes and demulsifiers to meet the requirements of being environmentally friendly and economically competitive. In this study, to deal with the problem of contamination of emulsified oil with water, magnetic manganese ferrite nanoparticles (MnFe2O4) were synthesized by coprecipitation method, then chitosan (CS) was applied on the surface of nanoparticles to synthesis a new compatible demulsifier of MnFe2O4NPs@CS. Next, the demulsification performance of the newly synthesized demulsifier, which is superparamagnetic and superhydrophobic, was evaluated. In particular, the effects of pH and demulsifier dosage on oil emulsion separation efficiency have been studied and investigated. The results of light transmission analysis showed that the optimal dose of demulsifier for maximum demulsification efficiency is about 0.4 g/l. Furthermore, this new synthetic compound has at least 7 cycle lifetimes, and increasing cycles has almost no effect on its demulsification performance. In addition, the demulsification mechanism of the compound was also investigated. The results show that the emulsified oil effectively adheres to the MnFe2O4NPs@CS demulsifiers through electrostatic attraction under acidic and neutral conditions.