Due to the temperature limit during the procedure of marine heavy oil exploitation, electric submersible pump oil production cannot meet the requirements of offshore oil. A new oil pumping equipment must be developed to replace the electric submersible pumps. On account of the restriction of offshore platform, the pumping units widely used in onshore are not suitable for offshore oil production, while the hydraulic pumping units are received widespread attention. The domestic and foreign research progress and current situation of the hydraulic pumping units were summarized which advantages and disadvantages,working principle were analyzed.Their balance methods were contrasted，the characteristics of hydraulic pumping unit for offshore platform were reached.