The invention relates to a temperature measurement system based on YAG: Dy fluorescence lifetime measurement as well as a test method and application thereof. The temperature measurement system comprises a signal transmitter, a UV-LED (Ultraviolet-Light Emitting Diode) ultraviolet light source electrically connected with the signal transmitter, a temperature measurement probe and a temperature signal processing unit used with the temperature measurement probe, wherein the temperature signal processing unit comprises a filter, a photomultiplier detector, as well as a resistor box and an oscilloscope electrically connected with the photomultiplier detector in sequence; the surface of the temperature measurement probe is coated with a YAG: Dy fluorescence layer, and the temperature measurement probe is connected with the UV-LED ultraviolet light source and the filter by optical fibers respectively; and the temperature measurement system is used for measuring the temperature of an aero-engine or a ground gas turbine in a working state. Compared with the prior art, the temperature measurement system has the characteristics of high measurement temperature (1080-1700 DEG C) and high temperature accuracy, adapts to the temperature measurement under different environments by changing the shape of the temperature measurement probe, does not influence the temperature field, and is high in temperature precision and wide in application range.