The physical and mechanical behavior of limestone，retrieved from five different places，exposed to temperatures up to 800 ℃ has been investigated experimentally at laboratory scale. Scanning electron microscope (SEM) experiments were conducted for observations of the microscopic structure. Uniaxial compressive and Brazil split testing and other measurements of geometric and bulk density changes were performed on the specimens after thermal treatment. The compressional wave velocity is correlated to mechanical parameters. Damage factors based on elastic modulus，compressive strength and tensile strength are compared with that from compressive wave velocity. Effect factors of degradation of limestone subjected to high temperature are discussed. Results show that internal defects of samples increase gradually with temperature. Compared to untreated specimens，as the temperature increases，bulk density，compressive wave velocity，elastic modulus，tensile and compressive strength reduce，while the porosity increases by both inducement of new cracks and development of existing cracks. Compressive strength and tensile strength and elasticity modulus increase with increasing compressive wave velocity which correlates well with mechanical parameters. Hence the compressive wave velocity could be used as an effective alternative for estimating the mechanical parameters of rock. Damage factor increases with increasing temperature. Strong correlations between damage factors based on elastic modulus，compressive strength and tensile strength and compressive wave velocity are found. Limestone samples from five different places show different physical and mechanical properties as a result of different mineral composition， structure and diagenesis.