Background　Auxiliary oxygen is advantageous to the prevention and treatment of hypoxemia in patients with spontaneous breathing， but increase the difficulty of respiratory function monitoring on the patients. If respiratory depression do not timely monitor， discover and treat， it can lead to apnea or even stop breathing， etc， accordingly endanger the patients’ life.　Objective　To review the several methods of monitoring patients spontaneous breathing in clinic at present.　Content　Methods which monitor respiratory function at present include clinical signs observasion， oxygen saturation with pulse oximetry（SpO2）monitoring， capnography， and percutaneous oxygen partial pressure/carbon dioxide partial pressure instrument monitoring. In this paper， it is introduced that the principle and effectiveness of these methods which were used clinically and their advantages and disadvantages.　Trend　To understand and use these monitoring methods for respiratory monitoring and management of patients， in order to ensure patient safety.