Abstract: In the process of particulate reinforced metal matrix composites the injection of the solid particulate into the molten metal is computed in this paper.By considering the resistance for the injection of a particulate as comprising drag,surface force and buoyancy,a criterion has been derived.For the implant of a particulate there is a minimum impinging velocity of a particulate onto the melt.Larger diameters of particulates,improvement in the wetting condition,and an increase of kinetic energy of particulates will favor the initiation of particulate transfer to melt.