In order to make the flame detector work better in wide temperature range, the temperature characteristics of dark resistance of lead PbSe sensor are discussed. According to the detection principle of lead PbSe sensor, based on the negative temperature coefficient characteristics of lead PbSe sensor, the dark resistance of certain type of lead PbSe sensor is tested in a range of temperatures. The temperature resistance curve of lead PbSe is fitted and the error is analyzed. Results show that the calibration method can be used for fast determining the sensor temperature characteristics, and the method also can be used for relative application.