The utility model relates to the technical field of sealing devices, in particular to a pressure test sealing device of a liquid
rocket engine jet
pipe, which comprises a base, a supporting cylinder, a sealing ring and a driving
assembly. According to the utility model, through the arrangement of the sealing ring which deforms under pressure, after the spray
pipe is placed, the driving
assembly drives the upper end of the sealing ring to move downwards, so that the sealing ring deforms and bulges outwards, the
diameter of the sealing ring is increased, the
throat part of the spray
pipe is blocked until the sealing ring cannot deform, and then a liquid pressing sealing performance test is carried out. Through the sealing mode, the sealing of the
throat part is ensured, so that the problem that the sealing effect of the
throat part of the spray pipe cannot be ensured in the prior art is solved, the time of the preparation work of the sealing performance test is shortened, and the
test efficiency is improved. And the larger the downward moving distance of the upper end of the sealing ring is, the larger the deformation degree of the sealing ring is, and the larger the
diameter of the sealing ring is, so that the device can adapt to spray pipes with different throat sizes, and the universality is improved.