Abstract: A leak-proof structure of an oil pipe connector includes: a connector cylinder, being a hollow housing, and having an oil inlet at a front end, and an oil outlet at a rear end, and a switch base interconnected to a shaft hole in the connector cylinder; a control device, installed in the connector cylinder; a switch device, having a transmission shaft, inserted into the shaft hole and linked with the control device, and a switch handle coupled to the top of the transmission shaft; a leak-proof device, having a bearing slot below the shaft hole, and a first leak-proof slot, a circular latch slot and a second leak-proof slot above the leak-proof device, and a bearing being disposed below the bearing slot, and a first O-ring, and a latch ring, a second O-ring for achieving a leak-proof effect.