The thermal insulation performance of titanium honeycomb sandwich panels is evaluated by experimental method. The influence of different geometric parameters of honeycomb sandwich panels, such as core diameter, core cell height and core cell wall thickness, on the thermal insulation performance is studied at 300 ℃; the sensitivity of above parameters to the thermal insulation performance is analyzed; moreover, the equivalent thermal conductivity of titanium honeycomb sandwich panels is tested at different temperature. The experimental results show that increasing the core cell height and core diameter and decreasing the core cell wall thickness can improve the insulation performance of titanium honeycomb sandwich panels; the sensitivity effect of honeycomb core height on the thermal insulation performance is the greatest，followed by the core cell diameter, and that of core cell wall thickness is the smallest; the equivalent thermal conductivity increases with the increase of temperature and is roughly about 3%—5% of the titanium materials.