Abstract: In this paper,the kinetic process and the possible incorporation mechanisms are analysed between particulates and matrix of particulate-reinforced metal matrix composites by spray co-deposition.For the first time it is presented that the injection mechanism is the unique incorporation mechanism between ceramic particulates and aluminum matrix,where ceramic particulates are poorly wetted by aluminum melt.Furthermore,the expression of the critical deposition velocity of a particulate,above which the particulate could be incorporated into matrix by the injection mechanism,is deduced from the balance of forces acting on the particulate by the liquid layer of the composite ingot.On the basis of the injection mechanism and a large number of experiments,a new method is developed to inject SiC particulates into the atomized spray,and W10 SiC_P/Al compsites with low segregation of SiC particulates and volume fraction of SiC particulates up to 14.7% were obtained.It is seen that the injection mechanism could predict the experimental results effectively.