Abstract: The crude oil emulsion formed by oil-water mixture in the process of oilfield gathering and transportation has complicated rheological properties, which may affect the safe and economic operation of pipelines. In order to explore the viscosity reduction effect of magnetic treatment on waxy crude oil emulsion, the viscosity change of emulsion was experimentally studied by adjusting the magnetic field intensity, as well as the temperature and time of magnetic treatment, with the self-developed static permanent magnet treatment device.Then, the crude oil viscosity and oil-water interfacial tension before and after magnetic treatment were measured, the droplet distribution of emulsion was observed, and the reason for emulsion viscosity reduction was analyzed. Through the magnetic treatment experiment, it is found that the viscosity reduction rate of the emulsion is the highest(14.5%) when the magnetic treatment lasts 10 min at the magnetic treatment temperature of 58 ℃ and the magnetic field intensity of 200 mT. It is also found through the interface and microscopic experiment that the oil-water interfacial tension of the emulsion decreases after magnetic treatment, the droplet distribution remains unchanged after the application of different magnetic treatment conditions, and the viscosity of emulsion is reduced under the action of magnetic field that decreases the oil-water interfacial tension and crude oil viscosity. Generally, the research results could provide guidance for the viscosity reduction and transportation technology of waxy crude oil emulsion, thus ensuring the safe gathering of crude oil.