TiB2/Cu matrix Interpenetrating phase composites (IPCs) with high ceramic content (~vol.83%) were prepared adopting high temperature sintering and subsequently melt-infiltration. The morphologies and microstructures of TiB2/Cu IPCs before and after thermal ablation were studied by SEM and EPMA. The thermal shock behavior and ablation-resistance of TiB2/Cu IPCs were investigated using plasma arc heating. The results showed that no crack was found on the ablated surface during the process of instantaneous heating and cooling, which revealed that TiB2/Cu IPCs have a good thermal shock resistance. Melt Cu phase presented obviously a gradual distribution among the ablation zone, transition zone and matrix zone, and no metal phase was detected near the ablation zone, it means that the melt play a role of sweat cooling during elevated temperature. The ablation-resistance mechanisms mainly include sweat cooling, chemical ablation and mechanical denudation.