On the basis of the results obtained by relevant literature at home and abroad, the quantified expressions for clay brick, mortar, and brick masonry were established, and some existing problems were summarized. Analysis shows that at high temperature, the compressive strength of clay brick decreased linearly with the increase of temperature, and the reduction coefficient of the compressive strength of clay brick was 0.53 at 1 000 ℃. When the temperature was lower than 600 ℃, the compressive strength of clay brick after high temperature decreased linearly with increasing temperature, and the compressive strength at 600 ℃ was about 56.2% of that at room temperature. The compressive strength of cement mortar after high temperature decreased with rising temperature. With temperature between 300 and 800 ℃, the reduction coefficient of the compressive strength of cement mortar after high temperature increased with the increase of water cement ratio when it was lower than 0.45, and it decreased when the water cement ratio was over 0.45. The compressive strength of clay brick masonry decreased with increasing temperature. Finally, formulas for calculating the compressive strength of clay brick, mortar, and clay brick masonry after high temperature were established.