A kind of oil-based multiphase slurry composed of heavy oil-coal powder-water (synfuel) was prepared by using suitable dispersant and emulsifier. The effects of components content, experiment temperature and dispersant content on its rheological properties have been investigated. It was observed that the synfuel showed pseudoplastic behaviour with apparent yield stress, and the apparent yield stress increased with increasing inner phase coal and water content. It was also observed that the apparent viscosity of the synfuel decreased with increasing temperature, and the apparent viscosity decreased with increasing dispersant content.