The invention discloses a temperature measuring device adopting a plurality of infrared sensors and its method. The temperature measuring device consists of a housing, a main control circuit board unit set in the housing, a power supply unit and an infrared sensor set at the head of the housing, wherein the main control circuit board unit is a main control circuit board, and a main control Microcontroller Unit, a signal acquisition circuit, a display screen, a power supply and a control key integrated in the main control circuit board. The method is to calculate and output the accurate target temperature through infrared sensors combined with Microcontroller Unit, at the same time, it can effectively identify such as abnormality of measurement area, abnormality of user measurement method and so as to improve the effectiveness of measurement results.
