Abstract: Offshore oil wells are geographically dispersed, and their single-well testing cost is high. In this paper, therefore, an online production metering method for offshore electric pump wells with capillary piezometry was studied in order to grasp the production change trend of oil wells in time, improve the production management level of offshore oil wells and realize the intelligent production management of offshore oilfields. According to the principle of conservation of energy that the input power of downhole electric pump is equal to the output power of downhole motor, the mathematical model for the on-line production calculation of electric pump wells with capillary piezometry was established in consideration of the influence of the change of motor parameters, combined with the borehole multiphase flow calculation method and the flow rate measurement correction method. In addition, its solution method was researched. Field application indicates that combined with the periodic correction on measured flow rate, the calculation result of this method is better coincident with the measured result with the maximum relative error less than 5%. By virtue of the method established in this paper, on-line production metering of electric pump wells can be realized, and their production trend can be reflected in time. In conclusion, this technology can reduce the operation cost of offshore oilfields significantly, and is of great significance to improve the production management level of offshore electric pump wells.