The invention discloses a lining-saved oil pump which consists of an oil pump driving gear (1), a pump body (2), an inner rotor (3), an outer rotor (4), a transmission shaft (5), an idler gear (6) and an idler shaft (7). Due to the design of the oil pump, the mechanism and the process of the oil pump are simplified, the cost is lowered, and the service life of the oil pump is prolonged.