Aiming at the problem that the amount of Oxygen remaining and available time can not be accurately predicted while an astronaut conducting extravehicular activities(EVAs)in EVA spacesuit.Research the oxygen consumption process of EVA spacesuit.The model and algorithm of oxygen consumption are established by the gas state equation including compressibility and temperature coefficient,combined with human metabolism and micro leakage characteristics of spacesuit.Experimental data show that the orecast model and algorithm hasing high accuracy and practicability.