In this work, a novel magnetic demulsifier was synthesized by a facile way within one step. The propyleneoxide-ethyleneoxide block polyether, one of the most frequently used demulsifier in petroleum industry, was endowed with the magnetism by reacting with iron (III) acetylacetonate. The as-prepared magnetic demulsifier was characterized by transmission electron microscopy (TEM), superconducting quantum interference device (SQUID), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The magnetic demulsifier showed excellent demulsification performance for water in crude oil emulsion. The demulsification process was revealed by using confocal microscope. Besides, the used magnetic demulsifier could be readily recycled by magnetic separation and solvent washing, and it presented excellent demulsification performance within 3 cycles. The findings in this work might provide a facile approach to prepare varieties of magnetic demulsifiers. (C) 2016 Elsevier B.V. All rights reserved.