The invention relates to the technical field of butterfly valves, in particular to a 
butterfly valve with high tightness and a using method thereof. The 
butterfly valve comprises a valve body and a 
pipe body communicating with the valve body, a rotating sleeve is fixedly connected to the bottom of the inner wall of the valve body, and the rotating sleeve sleeves a rotating rod. According to the 
butterfly valve with high tightness and the using method thereof, through improvement of the valve, after the valve is closed, a rotating 
handle is pressed downwards, so that a clamping sleeve extends into a semicircular groove and is meshed with a gear shaft, a movable foot enables an overturning piece to open a fixed seat and an overturning plate downwards, a rubber block extrudes a circular plate outwards, and a rubber sleeve on the circular plate is embedded into a limiting ring sleeve; and at the moment, the valve seals a valve 
body cavity, a gear belt on a shaft sleeve rotates on a transmission gear sleeve, so that the gear belt drives the gear shaft to rotate, when the gear shaft rotates, a lead screw on the gear shaft rotates, at the moment, a ball sleeve moves towards the rear side, a sealing sleeve makes contact with the valve, so that after the valve is closed, the 
pipe body and the valve body can form a highly-
closed state, so that the situation of fluid overflow is avoided.