Abstract： Objective To observe the oxygen-breathing efficacy by using different breathing apparatuses during normal pressure oxygen-breathing treatment and HBO treatment (HBOT) in the multi-seats chamber.Methods Changes in curve of transcutaneous oxygen partial pressure (TcPO2) for the 30 subjects,who had oxygen-breathing both at normal pressure and at a pressure of 0.22 MPa by using different types of apparatus were monitored continuously.Results (1) The curves of normal TcPO2 both at normal pressure and at 0.22 MPa were displayed in three stages:the compressing stage (1-5min after oxygen-breathing started until peak was reached) ; the plateau peak stage (the time when the peak arrived till decompression started) ; the decompression stage (the time when decompression was started till 20 minutes after oxygen-breathing was terminated).The elevation and declining of the curve synchronized with oxygen-breathing.(2) Oxygenbreathing by using different types of breathing apparatus tended to induce changes in the TcPO2 curves.(3)Before entrance into the chamber,instruction on the correct wearing of oxygen-breathing apparatus was an important measure for maintenance of the TcPO2 curves.Conclusions The TcPO2 curves synchronized with oxygen-breathing and was obviously affected by different types of apparatus.The TcPO2 curve could be used as an objective indicator for dynamic and real-time monitoring of oxygen-breathing efficacy in the multi-seats chamber.