The invention discloses an oil leakage preventive type roots flowmeter. The oil leakage preventive type roots flowmeter comprises a casing, a rotor, a rubber sleeve, a propping ring, a valve and a torsion spring, wherein a gland is arranged on the left side of the casing, the rotor is arranged in the gland in a penetration manner, the outer side of the rotor is rotationally connected with the gland through a bearing, an oil leakage preventive assembly is arranged on the outer side of the rotor in a sleeving manner and on the right side of the bearing and comprises the rubber sleeve and the propping ring, the propping ring is arranged on the inner side of the rubber sleeve, the right side of the propping ring is fixedly connected with the gland, and the inner edge part of the left side of the rubber sleeve is connected with the inner edge part of the right side of the bearing. The left end part of the propping ring is propped against the inner end part of the rubber sleeve, so that thelower end of the left side of the rubber sleeve is propped against the inner edge part of the right side of the bearing, the upper end part of the propping ring is propped against the side wall of therubber sleeve, the outer side of the rubber sleeve is enabled to be tightly attached to the gland, so that a path of lubricating oil leaking into the casing is closed, leakage of the lubricating oilis prevented effectively, and service life of the oil leakage preventive type roots flowmeter is prolonged.