································································································································································································································Abstract TiB 2 -reinforced iron matrix composite (Fe-TiB 2 ) powder was in-situ fabricated from titanium hydride (TiH 2 ) and iron boride (FeB) powders by the mechanical activation and a subsequent reaction. Phase formation of the composite powder was identified by X-ray diffraction (XRD). The morphology and phase composition were observed and measured by field emission-scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The results showed that TiB 2 particles formed in nanoscale were uniformly distributed in Fe matrix. Fe 2 B phase existed due to an incomplete reaction of Ti and FeB. Effect of milling process and synthesis temperature on the formation of composite were discussed.