The utility model relates to the technical field of hydraulic metal structure manufacturing, in particular to a plugging device for a hydrostatic test of a pressure steel pipe component and an installation method of the plugging device. Reinforcing rings are distributed on the inner wall of the pressing cylinder, a partition plate is vertically arranged between each upper layer of reinforcing ringand each lower layer of reinforcing ring, and the outer walls of the two ends of the pressing cylinder are sleeved with base plates respectively. The plugging choke plug has the advantages that the reinforcing rings are arranged on the inner wall of the pressing cylinder in the circumferential direction, the partition plates are arranged between the reinforcing rings, and compared with a pluggingchoke plug in the prior art, the plugging choke plug is simple in structure and can provide enough strength; the device is installed on the inner wall of the bellows expansion joint, the formed closed space is small, the water filling time and the water pressure test time are greatly shortened, the construction period can be effectively shortened, and the construction cost is saved.