Abstract: In order to investigate the degradation law of mechanical properties of High Toughness Cementitious Composite (HTCC) under thermo-mechanical coupling, we experimentally prepared HTCC and simulated the operating conditions of gas storage facility of compressed air energy storage to carry out the temperature and pressure synchronous cyclic loading test, mechanical performance tests and microstructure tests. The uniaxial compression stress-strain curve, pore structure parameters and microstructure characteristics of HTCC were obtained, and the influence of thermo-mechanical coupling on the mechanical properties of HTCC and its micro-mechanism were studied. The results show that HTCC has high tensile strength, low elastic modulus, ultimate tensile strain up to 1.01~2.13%, obvious multi-seam cracking characteristics and tensile strain hardening behavior, the average crack width is below 60 μm, and it has good tensile toughness and crack control ability. The nonlinear segment of the rising section of the compression stress-strain curve of HTCC increases significantly and the peak strength decreases after the thermo-mechanical coupling test. The influence of temperature and stress on the mechanical properties of HTCC under temperature and pressure synchronous cyclic loading is different. Within the temperature range of 25-150 ℃, as the cycling temperature increases, the porosity of HTCC decreases and the compressive strength increases. When the cyclic temperature is the same, as the cyclic stress increases, the porosity of the HTCC matrix increases, the pore size coarsens, and the compressive strength significantly decreases. Stress is the main influencing factor for the deterioration of the mechanical properties of HTCC. Based on statistical analysis of experimental data, the HTCC compressive damage constitutive model after thermo-mechanical coupling is established.