The invention provides a wireless temperature measuring device based on a spectrum technology and a method thereof. The wireless temperature measuring device comprises a power supply module, a first light source, a first photoelectric converter and an analysis module, wherein the power supply module provides an input current for the first light source; the first light source perceives a temperature of an object to be measured; a wavelength of measurement light emitted by the first light source under effects of the input current and the temperature covers an absorption line of at least one gas in the air; the first photoelectric converter is used for converting the measurement light after being absorbed by at least one gas into a first electrical signal and transmitting to the analysis module; and the analysis module processes the received first electrical signal according to an absorption spectrum technology so as to acquire a position of an absorption peak corresponding to the at least one gas, and uses a mapping relation among an output wavelength of the first light source, the temperature and a current so as to acquire the temperature of the object to be measured, wherein the temperature is perceived by the first light source. The device and the method of the invention have advantages that precision is high; the structure is simple; cost is low and so on.