Abstract: Hydrostatic test pressure and its advantages and disadvantages have been discussed in detail. The paper indicated that the hydrostatic test pressure is about 40%~45% of the plastic instability pressure; Hydrostatic test stress criteria allowable pressure is about 50%~75% of the plastic instability pressure; Hydrostatic test may improve and increase the loading capability of the pressure vessel and decrease the failure possibility by hydrostatic test mechanism; Hydrostatic test is the useful and efficiency examination method and inspection technology for the leakage and strength of the pressure vessels; Periodic hydrostatic test during operation may establish the maximum defect in the pressure vessel or the maximum loading so that to provide basis and data for continuous operation, but the pressure of the periodic hydrostatic test does not exceed the first hydrostatic test pressure. The overpressure test and the warm pre-stressing test and harmful effects of pressure test need to be researched in depth.