In this paper

the finite element software is used to simulate the mechanical properties of insulator of 40.5 kV porcelain post insulator under the condition of temperature upheaval

including the temperature stress produced by the temperature upheaval and the effect on the bending load and torsion load with the temperature range of-40℃～+80℃（the initial temperature is 20℃）.It is found that under the conditions of low temperature or high temperature

the stress concentration phenomenon appears in the connecting position of different medium of porcelain post insulator.At the same time

when the bending load is applied

the high temperature will make the porcelain post insulator bear greater stress

while the stress decreases with the decrease of the temperature at low temperature;and when the torsional load is applied

the stress of the porcelain column is different at different positions and temperatures

the stress of the upper porcelain root decreases with the increase of temperature

the stress of the lower porcelain root increases with the increase of temperature

which provides some theoretical guidance for the operation and maintenance of insulators in different environments.