The invention discloses an oil returning gas removal device and a lubricating oil system, and relates to the technical field of power devices. The oil returning gas removal device is arranged in an oil tank of the lubricating oil system and comprises a connecting part, an oil returning pipe assembly, a sleeve and a filter assembly; the connecting part is used for mounting the oil returning gas removal device in an oil returning hole in the inner wall of the oil tank, the inlet end of the oil returning pipe assembly is connected with the connecting part, the sleeve is arranged at the outlet endof the oil returning pipe assembly, the sleeve and the oil returning pipe assembly form a continuous pipeline, multiple oil passing holes are formed in the periphery of the wall of the sleeve, the filter assembly is detachably arranged on the circumferential outer side and the bottom of the sleeve, and the filter assembly is provided with a filter net with the hole diameter smaller than 0.3 mm. Oil returning turning over and bubbles generated by traditional gravity oil returning can be avoided, the filter net of the filter assembly can effectively separate bubbles with the diameter above 0.3mm in the oil returning process, the gas containing amount in lubricating oil can be effectively reduced, the lubricating effect of the lubricating oil is ensured, and cavitation noise caused by gas containing of the lubricating oil can be reduced.