The experiment of Design and Calibration of Thermistor Thermometer is a required design and research experiment for science and engineering students in our university． The Geometer’s Sketchpad was used to optimize the experimental design process，which improved the efficiency of experimental design and obtained the parameters of the components in a short time ( t = 25．0 ℃ as an example) : Power supply E = 2．009 V， Ｒs = 5 000 Ω，Ｒ1= Ｒ2 = 3 375 Ω，such a combination of parameters make thermistor thermometer can measure the temperature 25． 0 ℃ ～ 75． 0 ℃ ，the linear relationship between the current of the micro-ammeter and temperature has reached the optimal state． At the same time，the maximum power of the thermistor is 0．434 8 m W，which is far less than the maximum power of 1 m W，proving that the design is successful．