A physiological monitoring system is provided. The physiological monitoring system includes a feature extraction device, an identifier, a processor, a physiological sensing device, and a vital-sign detector. The feature extraction device extracts biological information of an object to generate an extraction signal. The identifier receives the extraction signal and verifies an identity of the object according to the extraction signal. The processor receives the extraction signal and obtains at least one biological feature of the user according to the extraction signal. The physiological sensing device senses a physiological feature to generate a bio-signal. The vital-sign detector estimates vital-sign data of the object according to the bio-signal and the at least one biological feature.