The present disclosure provides a method and a system for wirelessly and passively measuring temperature and devices forming the system. The method includes: receiving an energy feedback radio frequency (RF) signal by a temperature measuring end; converting the energy feedback RF signal into electric energy and storing the electric energy; and starting the temperature measuring end after obtaining the electric energy, and transmitting a RF signal under the current temperature to a terminal, and calculating the current temperature through the terminal. The method, the system and the devices forming the system provided in the present disclosure are capable of activating the crystal oscillator or the ceramic oscillator wirelessly and passively, therefore, the method, the system and the devices can be used to wirelessly and passively measure temperature, which is convenient.