Abstract: The liquid inflow of hydraulic pressure test is an important parameter in the testing process for gas cylinder, and it's also a key factor in the design of the test device and equipment selection. For steel gas cylinder, its liquid inflow of hydraulic pressure test is divided into two parts: deformation increment and hydraulic medium compression amount, the theoretical calculation formula of liquid inflow amount and the partial calculation formula of component parts of liquid inflow amount are obtained after analysis. Through the example test, measurement and comparison, it is found that the maximum error between the theoretical calculation value and the experimental measured value is only 2.3%; the hydraulic medium compression value accounts for larger proportion of the liquid inflow, which verifies the reliability and correctness of the theoretical calculation formula. This provides theoretical support for obtaining the liquid inflow of cylinder hydraulic test and analyzing the proportion of each part of the liquid inflow quickly and effectively.

Key words: gas cylinder, hydrostatic test, liquid inflow, deformation increment, strain test