The mechanical alloying (MA) route was used to mix uniformly boron powder, FeMo powder and titanium powder. The mixed powder was vacuum hot press sintered and TiB was formed in-situ during the process. Typical microstructure of the composites has two kinds of areas under optical microscope (OM): in situ TiB reinforced Ti MMCs and the isolated unprocessed material. TEM investigation of the TiB reinforced composites show that these areas are made up of in situ TiB reinforced and Ti matrix. The size and distribution of in situ TiB are different in boundaries and inner of and Ti phases. Most of the in situ TiB needles are random distributed. The transverse section of the in situ TiB needle is hexagonal. The interface between in situ TiB and the Ti MMCs is clear, flat and sharp without any interfacial reaction. The strength and Youngs modulus of the TiB reinforced TMCs decreased with the increasing of in situ TiB volume content.