A method and system is provided for monitoring a respiratory signal by radio. The method includes the steps of: converting a change in electric resistance, which is caused by a change in abdominal circumference measured through a rubber waistband that is made of conductive rubber and is mounted on a lower garment of a testee during respiration, into a voltage signal, performing A/D conversion on the voltage signal, and transmitting the converted digital signal to a short distance by radio using a wireless communication protocol for ZigBee; and receiving the respiratory signal transmitted by radio, transmitting it to a computer unit by wire through an RS-232 port that is a serial communication port, and enabling a tester to monitor the respiratory signal through a screen.