The invention discloses a passive wireless temperature sensor and belongs to the field of wireless sensing. The passive wireless temperature sensor comprises a receiving antenna, a radio frequency energy collecting module, a protection module, a power management module, a modulation and demodulation module, a data management module, a temperature measurement module, an external sensor module, a wireless transmitting module, a transmitting antenna, an auxiliary power supply, a wireless energy transmitting module and a receiving module. The radio frequency energy collecting module and the wireless energy transmitting module are adopted to generate current through an electromagnetic induction principle to provide power to a circuit in environment to be tested, the problem of power supply of the circuit in a special environment is solved, a schottky diode is used as a temperature measurement component, a schottky diode adopting a special material is used as a temperature-collecting element, the schottky diode has the characteristics of high temperature resistance, high voltage and high frequency, so that the problem that a common sensor fails in the special environment is solved; no direct power supply unit and data transmission line exists in the circuit of the environment to be tested, and the passive wireless temperature sensor is simple in structure and convenient to arrange.