Abstract: The coupling mechanism between temperature fields and stress fields is briefly analyzed, and a quantitative method for calculating the coupling parameterPTCis introduced in detail based on the thermo- elasticity effect and the thermal diffusion equation. The proposed quantitative parameter is used to evaluate the thermo-elasticity coupling effect. The thermo-elasticity coupling effect of several kinds of common rocks are calculated, with a result showing that usually the value ofPTCis of the order of 10-3. In the mean time, a preliminary discussion on the practicability and significance of the dimensionless parameterPTCin engineering application is made.