Ｏｂｊｅｃｔｉｖｅ　To study the accuracy and characteristic of domestic pulse oximeter（POM） used in healthy volunteers under controlled hypoxemia， and to provide scientific proof for safe and effective clinical application.　Methods　Healthy volunteers were made hypoxic by inhaling mix gases of oxygen and nitrogen， and were monitored by two pulse oximeters with Masimo and Nellcor pulse probe， respectively. Monitoring interval of pulse oxygen saturation（SpO2） was 70% to 100%. When it reached around the five target values（>95%， 92%， 85%， 78%， 70%）， readings of SpO2 were recorded and arterial blood sample were collected at exactly the same time for blood gas analysis.　Results　Differences of SpO2 detected by Masimo and Nellcor probes with arterial oxygen saturation（SaO2） determined by blood gas analyzer were within the ISO9919：2005 standard range（Arms=2.16 and 2.32， respectively）. Bias（SpO2-SaO2） of SpO2 of Masimo probe were 0.93% and -1.45% when SpO2≥80% and <80%， while those of Nellcor probe were 0.16% and -1.91%. There was significant difference between two probes（P<0.01）.　Conclusions　Domestic pulse oximeters using Masimo and Nellcor probe can both accurately reflect the oxygen saturation in different degree of hypoxemia. But the readings of Nellcor probe are generally lower than those of Masimo probe due to different principles. As SpO2 goes down， the bias enlarge towards the negative value， leading underestimation of oxygen saturation， especially when SpO2<80%.