In the extreme conditions of launch vehicle in a space, such as cryogenic temperature and low-gravity environment, the mass gauging of remaining propellants becomes a difficult problem. Pressure–volume -temperature (PVT) method is one of the attractive mass gauging methods under low-gravity due to its simplicity and reliability. PVT gauging experiment with various mass flow rates of helium injection is carried out with the experimental apparatus creating cryogenic homogeneous condition as the condition of low-gravity. Experimental results are analyzed by a novel PVT gauging analysis method which considers all instantaneous changes of pressure and temperature in the ullage volume with small time intervals. It is observed that the gauging error from the novel PVT gauging analysis is –0.11% with 2 slpm mass flow rate of helium injection.