A plunger valve contains a valve (1), a lower seal ring (2) positioned among valve channels from bottom to top, a annular support frame (3), a upper seal ring (5) and a plunger (4) positioned in a seal cavity formed from the annular support frame and the upper seal ring above the lower seal ring via a valve stem (6). The utility model is characterized in that the seal manner integrates via the fit of an arc surface and a conical surface between a lower seal ring surface of the plunger (4) and the seal ring surface of the lower seal ring (2). The utility model changes the radial seal between the plunger and the lower seal ring in the prior art into a end plane seal and changes the seal manner of plane fit into a linear seal of the arc surface and the conical surface fit, which forms the seal of a certain angle when the lower end of the plunger and the lower seal ring are closed and consequently solves the problem of the radial seal of the prior plunger valve plunge and the seal ring being not able to make up a micro distortion caused by a thermal expansion, avoiding the drip and leak phenomenon caused by the thermal expansion.