The utility model discloses a power station pressure is ball valve blocking device for oil pipe, it includes ball valve valve rod (1), and the top of ball valve valve rod (1) is connected with spacing piece (2), and spacing piece (2) below still is provided with packing flange (3), the both ends of packing flange (3) all are connected with packing clamp bolt (4), and the middle part of packing flange (3) is connected with mechanical lock (5), be equipped with lock core (6) in mechanical lock (5), the top of lock core (6) is connected with spring bolt (7), packing clamp bolt (4) and spring bolt (7) all are located the rotation route of spacing piece (2). The utility model discloses a spacing piece and two packing clamp bolt restrict the rotation stroke of ball valve valve rod, and the spring bolt of while through the mechanical lock comes the position of locking and limiting piece to can rotate at the ball valve valve rod and lock when opening the ball valve or close the position of ball valve. The utility model discloses the security not only can be improved, economic loss can also be avoided.