The invention relates to an air floating shaft and in particular to an air floating shaft based on Z-direction control of a six-freedom-degree air floating table. The air floating shaft aims at solving the problem that an air pressure compensation mode of an existing air floating platform is usually implemented through a semi-automatic gravity compensation mechanism, so that the control accuracy of the air floating platform is low. The air floating shaft comprises an outer air floating bearing sleeve, an inner air floating bearing sleeve and multiple nitrogen nozzles. The inner air floating bearing sleeve is inserted in a cavity of the outer air floating bearing sleeve. The nitrogen nozzles are evenly distributed on the inner side wall of the cavity. The air floating shaft is used in the field of physical simulation.