The invention discloses a steam turbine lubricating oil high-level oil tank system. The steam turbine lubricating oil high-level oil tank system comprises a main oil tank, an oil pump, an oil supply pipeline, a bearing box and an oil return pipeline which sequentially communicate with each other according to a lubricating oil circulation sequence, the oil supply pipeline communicates with an oil cooler and communicates with an oil charging pipeline, the oil charging pipeline communicates with a high-level oil tank, and a high-level oil supply pipeline communicates between the high-level oil tank and the bearing box. The steam turbine lubricating oil high-level oil tank system has the beneficial effects that an existing system does not depend on an electrical system, can automatically and stably control the oil supply pressure, only has the requirement for the lowest arrangement height of the oil tank, has no requirement for the structural form, can maintain the oil temperature and the oil level of the high-level oil tank, and has an online testing function. According to the steam turbine lubricating oil high-level oil tank system, the volume of the high-level oil tank can be effectively reduced, the arrangement requirement of the high-level oil tank is lowered, regular tests can be carried out, the safety of a unit lubricating oil system is enhanced, and oil cut-off and bush burning accidents are avoided.