Abstract: Using a special high speed tribo-tester, tribological behaviors were investigated on aluminum composites reinforced by SiC particles and compacted graphite cast iron with sliding velocity in the range of 40~100 m/s. Experimental results indicated that, under very high sliding velocity, dry sliding properties of the materials were influenced by combination effects of amount of friction heat produced, heat conduction ability, and melting point of the materials. Increasing sliding velocity and contacting pressure decreased the differences of tribological properties between two materials tested. Aluminum composites reinforced with SiC particles exhibited good performance at high sliding velocity (>100 m/s).