Objective:To compare the detection success rates (DSRs) of different kinds of near-infrared spectrum non-invasive hemoglobin monitors in high-altitude environments.Methods:One hundred and forty-four healthy volunteers of either sex, aged 18-50 yr, were assigned to one of 3 groups using a random number table method: simulated high-altitude 3 500 meter group ( n=35), 4 000 meter group ( n=55) and 4 500 meter group ( n=54). Hemoglobin was detected by Radical-7, NW-9002SHM, A5 and TensorTip MTX type hemoglobin monitors in plain environment and simulated environment at different altitudes, and the DSRs were compared.Logistic regression analysis was conducted to identify the risk factors affecting the success rate of instrument detection, and the cut-off value was determined by ROC curve and the Youden index. Results:In the simulated high-altitude environment of 3500, 4000 and 4500 m, the DSR of TensorTip MTX was significantly higher than that of Radical-7, NW-9002SHM and A5 ( P<0.001), and there was no significant difference in the DSR among Radical-7, NW-9002SHM and A5 ( P>0.05). Low SpO 2 was the main factor affecting the DSRs of the Radical-7, NW-9002SHM and A5 type hemoglobin monitor in high-altitude environment ( P<0.001), and the cut-off value of SpO 2 in determining the success of detection was 88.5%, 87.5% and 89.5%, respectively.The DSR of TensorTip MTX was not affected by low SpO 2. Conclusions:The DSR of TensorTip MTX hemoglobin monitor is minimally affected by the high-altitude environment and can be preferred in the absence of oxygen supply; when Radical-7, NW-9002SHM or A5 hemoglobin monitor applied in high-altitude environments, oxygen saturation needs to be increased to ensure a high DSR.