ln the experiment of " Design and Calibration of Thermistor Thermometer" , the rational selection olthe two resistors on the bridge ratio arm plays a crucial role in the suceess or failure of the experimental designThey afleet not only the resistance value of the comparison anm resistor and the power supply voltage, but alsothe heating power of the thermistor and the linearity of the calibration eurve,The author, with the aid of Desmossoftware and applying mathematical thoughts such as caleulus and the combination of numbers and shapes,determined the criterion for the impaet of the ratio arm resistance on the linear relationship between themieroampere indieation and temperature under the consiraint of the maximum power of the themistor, andobtained the relatively optimal parameter values, When using the optimal parameter combination, the circuit nolonly meets the power requirements but also achieves the optimal linearity of the calibration curve.Therefore, theoverall design has reached the expeeted goal.