Abstract:in order to make the high precision temperature measuring instrument meet the maximum allowable error of the instrument in the environment of 0 ℃~ 40 ℃, analyze the circuit characteristics of the high-precision temperature measuring instrument, test the instrument in high and low temperature environment, and summarize the influence of environmental temperature change on the measurement error of the instrument in non constant temperature environment, The compensation function of the environmental temperature change of the instrument is fitted, and the corresponding coefficient is extracted according to the test data of each instrument to compensate the environmental temperature of the instrument measurement results.