Series of FePt/Fe multilayers with different layer thicknesses have been deposited on Si substrates by magnetron sputtering and post annealing at different temperatures and durations. The structure, surface morphology, composition, and magnetic properties of the deposited films have been characterized by XRD, SEM, EDX and VSM. It is found that after annealing at temperatures above 500°C, FePt phase undergoes a phase transition from disorder fcc into ordered fct structure, and become a hard magnetic phase. For [FePt/Fe]n multilayer with varying Fe layer thickness, lattice constants and grain sizes change with Fe layer thickness and annealing temperature. The coercivities of [FePt/Fe]n multilayers decrease with Fe layer deposition time, and the energy product (BH)max shows a maximum with Fe layer thickness. Optimization on layer thickness leads a high (BxH)max value of 15.2MGOe for [FePt(8min)/Fe(4min)]8. The effects of quick annealing and Ag underlayer on the structure and magnetic properties were also studied.