To explore the mechanical properties and structural stability of the corbel reinforcement and the corbel adhesive at high temperature, ABAQUS software is employed to establish a simulation model for corbel member at smoke passage plate under fire on three sides, and the stress and displacement distribution of the corbel under different temperatures are examined. The results demonstrate the following: (1) The temperature of the adhesive closest to the bottom of the corbel exceeds the fire resistance limit (120 ℃) after 2 h at 1 200 ℃, resulting in melting, and the other two are basically not affected. (2) The displacement of reinforcement and corbel is small, no more than 9 mm, and their mechanical properties are gradually dominated by thermal stress and thermal expansion with increasing temperature. The corbel still remains 71% bearing capacity, and the short-term creep effect of high temperature can be ignored, thus the corbel does not fall off.