Abstract: The heavy oil accounts for over 50% in the proven reserves in China, but its high density and high viscosity makes it difficult to exploit and transport, so reducing heavy oil viscosity is of great significance. The ultrasonic technology has made some achievements in the application of heavy oil viscosity reduction, but it has not been applied on a large scale in the field. In order to investigate the effect of the ultrasonic wave on heavy oil viscosity reduction, a test platform composed of ultrasonic generator, rheometer, electronic balance, water bath etc. is designed. Based on the experiments, the influences of the electric power of the ultrasonic generator, the irradiation time and the initial viscosity of heavy oil on the reduction rate of heavy oil viscosity are investigated. The results show that the ultrasonic technology can get a better viscosity reduction effect only under certain conditions, which illustrates the applicability of ultrasonic technology in reducing heavy oil viscosity and increasing production and injection of oil wells. At present, it seems that the application of this technology in the actual wells of oil field and its viscosity reduction mechanism still need to be further studied.