TC4 titanium alloy honeycomb sandwich panel is manufactured by high-temperature brazing. In this paper, the mechanical performance parameters and failure modes of honeycomb sandwich panel are experimentally investigated via flatwise compression and three-point bending test subject to different temperatures. It is found by the test that flatwise compression elasticity modulus and strength of the honeycomb sandwich panel at 440℃ decrease to 35.2% and 61.7% of that at room temperature, respectively, indicating that higher temperature may result in lower compression elasticity modulus and strength. It is also found that the test temperature has no effect on the failure mode. On the other hand, it is noted in the three-point bending test that the failure mode changes, the flexural strength decreases, and that the maximum deflection increases with the increasing test temperature. It is also found that the bending performance of specimens in the L-direction is better than the W-direction. In addition, the face sheet of the bending specimen is ductile fracture, and the brazing zone is brittle fracture at room temperature as revealed by the experiment, while the brazing joints of surface/core debonding failure specimen is cleavage fracture a high temperature of 300℃.