A hyper-eutectic alloy, with nominal composition Ni-42Al-16Mo (at. %), was directionally solidified at growth rates ranging from 12~300μm/s by Liquid Metal Cooling (LMC) technique. Microstructural examination reveals that the NiAl-16Mo alloy was composed of primary Mo dendrite and NiAl/Mo eutectic cell in all the growth conditions employed. With the growth rates increasing from 12μm/s to 300μm/s, the volume fraction of Mo primary dendrite increased from 7.21% to 11.42%, while the size and the arm spacing of Mo primary dendrite reduces simultaneously. The corresponding room temperature fracture toughness (RTFT) and ultimate high temperature compressive strength (UTCS) decrease with increasing of growth rates, the toughening and strengthening mechanism of composite was also discussed.