Disclosed herein is a system for measuring the deflection of a rotating shaft in a wireless manner. The system includes a non-contact-type angle division device, a plurality of wireless contact-type displacement sensors, a plurality of wireless transmitters, a relay, and a data reader. The non-contact-type angle division device is placed on a vertical rotating shaft and measures and transmits the angle of rotation of the rotating shaft. The wireless contact-type displacement sensors are installed on the outer circumferential surface of the rotating shaft, and measure the strain of the rotating shaft. The wireless transmitters transmit data about the displacement of the rotating shaft measured by the wireless contact-type displacement sensor. The relay receives and relays transmission signals from the non-contact-type angle division device and the wireless transmitters. The data reader receives the transmission signals from the relay, and performs simulation reading.