Under or after high-temperature treatment, the physical and mechanical characteristics of limestone and marble change significantly. This study seeks to understand the effect of high temperatures on physical and mechanical properties (such as density, porosity, permeability, P-wave velocity, thermal diffusivity, elastic modulus, uniaxial compressive strength, peak strain and Poisson's ratio) of limestone and marble. The results indicate that, from room temperature to 300°C, most of the physical and mechanical indices of limestone and marble change relatively little, except for thermal diffusivity. Above 300°C (especially at 400–600°C), physical and mechanical characteristics change significantly, corresponding to the changes to minerals between 400 and 600°C. These results confirm the important link between physical and mechanical properties and heating temperature, and can provide the basis of theory and reference for related engineering.