Abstract: Conventionally, viscosity-reducing additives are deployed in annular spaces between tubing and casing to develop heavy oil,these operations are featured with uneven mixing of additives and produced fluids, poor viscosity-reducing performances and the low-efficiency of such additives. Under such circumstances, research has been conducted to reduce viscosity by swirl pumping in heavy oil producers. Its principle is that the viscosity-reducing additives can be injected into the hollow rod by the ground mixing system, and then placed under the pump by means of a central hollow rod. The rotation of propellers in the mixing system can sufficiently mix the produced fluids with a viscosity-reducing additives to generate an evenly dispersed mixture, by which the maximum efficiency of a viscosity-reducing additives and optimal performances can be achieved. This innovative technology is suitable for the heavy oil producers with depths of less than 1 500.00 m and fluid productivity of no more than 50 m3/d. It has been deployed in 21 heavy oil producers in the Shengli Oilfield with average pumping efficiency increment of 11%, accumulative oil increment of 5 310 m3, total reduction in consumption of viscosity-reducing additives of 9 t, and the extension of average production cycle for 81 d. Research results showed that the newly viscosity-reducing technology using pumping swirl for heavy oil production can give full play to the effectiveness of viscosity-reducing additives, with obvious oil increasing the effects with prospects for broad applications.