To study temperature variation of the detector chip irradiated by spectral unrelated laser, the platinum resistance thermometer is used to monitor temperature of the chip's back surface. The electron-hole pairs separative duty of the field in the junction depletion region is calibrated. The temperature of front chip surface is obtained by the experimental method of laser combination. It is found that both front and back chip surface have temperature rise, but the temperature of back chip surface is always higher than that of the front one in the irradiated process.