Fe/C/Si ultrafine particles (UFP) were synthesized by laser induced vapor-phase reaction method with a 150 W CW CO2 laser as light source and SiH4, C2H4 and Fe(CO)5 as rawmaterials. The instantaneous temperature of the reaction flame was measured by a SCIT infrared thermometer. The effects of processing parameters on this temperature have been studied. Detailed characterization of samples is presented, including chemical analysis, FT-IR, TEM and XRD results.