Screw one-way bypass valve

The utility model discloses a screw one-way bypass valve, which comprises a body, a valve rod, a spring and a screw cap, wherein a connecting thread is arranged on the outer tube wall of the body; the body is provided with a hollow cavity; an inner shoulder is arranged on the middle part of the inner wall of the body; the valve rod has a T-shaped structure, and comprises a sealed end and a rod body; a thread matched with the screw cap is arranged at the end, away from the sealed end, of the rod body; the spring is sleeved on the rod body between the inner shoulder and the screw cap. The screw one-way bypass valve is at an open position during trip-out, and drilling fluid in a water hole of a drilling tool can flow into an annulus, so that normal construction is ensured; the screw one-way bypass valve is at a closed position during running, drilling, connection making and pump stopping, so that impurities such as annulus mud sand and a thread membrane are effectively prevented from entering the water hole of t