Abstract: The Stability of high-speed aerostatic bearings is, in its nature, a problem of whirl vibration, which is a hindrance to the application in high-speed operations For aerostatic journal bearings running from zero to 240000 r.p.m.on rigid support, the changes of the whirl amplitudes with the rotational frequencies were measured. The experimental analyses of the effects of the supply pressure, bearing clearance, rotor unbalance etc, on the stability under high-speed operations were then conducted. A comparison of high-speed characteristics between five bearing configurations, I.e.slot-fed bearings, orifice compensated bearings, tangentially fed bearings and others has been made. We have found that two optimum clearances appeared on the onset speed of self-excited whirl versus clearance curve, and that the second optimum clearance value is far beyond the normal range. The stability of a slot-fed bearing is superior to that of a orifice compensated bearing, and the stability of single series bearing is better than that of two series bearing. The so-called"choking"also occurs in a slot-fed bearing. Finally, basic considerations for high-speed aerostatic bearings design are suggested.