The invention discloses an apnea detection method and a surface acoustic wave sensor, and relates to a measurement device for examining a respiratory organ. The apnea detection method comprises a transmitting step, a receiving step and a processing step; the transmitting step comprises an operation of transmitting radio-frequency radio to the surface acoustic wave sensor which is attached to the lower side of the nose of a detected object, wherein the surface acoustic wave sensor comprises an antenna for receiving the radio-frequency radio, a piezoelectric substrate as well as an interdigital electrode and a surface acoustic wave reflecting grating which are manufactured on the piezoelectric substrate, and the interdigital electrode and the antenna are electrically connected; the receiving step comprises an operation of receiving a radio-frequency signal which is returned from the antenna; and the processing step comprises an operation of extracting information representing a respiratory condition from the returned radio-frequency signal. The apnea detection method provided by the invention is simple to operate; and the adopted wireless passive flexible surface acoustic wave sensor, which is free from a power supply and connecting lines, is light in overall weight and quite light and convenient, and the surface acoustic wave sensor, which is free from the power supply, is safer and more reliable and is applicable to home use.