Backflow-preventing spherical sealing check valve and using method

The invention discloses a backflow-preventing spherical sealing check valve and a using method. The backflow-preventing spherical sealing check valve comprises a valve body, wherein a liquid inlet channel and a liquid outlet channel are formed in the valve body, a valve seat is arranged at the connecting position between the liquid inlet channel and the liquid outlet channel, and a stroke cavity is formed in the valve seat; the stroke cavity extends obliquely upwards in the direction of the liquid inlet channel, the liquid outlet channel is connected to the middle part of the stroke cavity, and a valve deck is arranged on the upper portion of the stroke cavity; a floating barrel is arranged in the stroke cavity, a valve cavity is formed in the floating barrel, and a valve ball is arrangedin the valve cavity; the floating barrel can slide along the stroke cavity, the lower portion of the floating barrel is in sealed connection with the inner wall of the valve seat, an adjusting cavitycommunicating with the liq