The present invention discloses a method for temperature conversion of a PT100 temperature sensor, comprising the following steps: S1: preprocessing a PT100 temperature sensor to obtain a regression constant A and a regression coefficient B in a current temperature range; S2: obtaining the measured value of the PT100 temperature sensor; S3: performing the data type processing on the measured value to obtain the temperature independent variable X; and S4, subtracting the regression constant A and the temperature dependent variable X from the product of the temperature independent variable X and the regression coefficient B to obtain the actual temperature value. By preprocessing the P100 temperature sensor, the most appropriate linear regression equation of the current measurement environment is calculated, and the available regression constants and regression coefficients are determined. The measured temperature value detected by the P100 temperature sensor is processed to obtain the accurate independent variable value, and the independent variable value is operated to obtain the actual temperature value.