Abstract: Hydraulic feedback pumps for heavy oil leaked frequently in the production of the No.2 Oil Production Plant ever since 2012, which reduced production. The production characteristics of pump leaking wells and the features of leaking positions showed that there were two major reasons for the leakage:(1) High water cut, hydrogen sulfide existence and high salinity speeded pump leakage. (2) Unreasonable structural parameters. For example, pumps 56/38 and 70/44 leaked due to small suction valve diameter. We can solve this problem by improving inlet valve structure, enlarging inlet valve and seat sizes, and improving valve seat material.