The signal stability of piezoelectric smart aggregates(PSAs) under environmental temperature changes is investigated to clarify the rules and its variation law is analyzed in this work.The research will lay a solid foundation for PSA based structural health monitoring (SHM). A small scale plain concrete beam pre embedded with PSAs is placed and tested in a thermostatic chamber and the PSA signal energy values for changing temperatures are recorded,and the relationship between signal energy values and temperatures is fitted by the test data.The experimental results show that the PSA signals change obviously and behave significantly nonlinear property which complies with the electro mechanical coupling coefficient of piezoelectric material.This is because the temperature change leads to the variation of elastic constants,reflecting the variation of electromechanical coupling coefficient on a macro scale.