The experimental designs and the characteristics of a laser range finder under -40℃ circumstance were investigated with ITO optical windows heated to keep observation from dew or hoarfrost at room temperature. Primary experimental results and data of laser range finder in low temperature circumstance were accumulated and discussed. To meet the demands of the performance inspection of the laser range finder in working condition

the designs of ITO windows set up on a low temperature cabinet

are used to confirm the quality inspection and calibration of the laser range finder before its leaving from factory.