Abstract: In situ TiB-Nd₂O₃-Ti composites were synthesized by ingot metallurgy.With optical microscope,scanning electronic microscope and transonic electron microscope,the microstructure,mechanical properties and failure mechanism of the in situ composites were investigated.It is showed that the reinforcements of composites are TiB and Nd₂O₃ which are distributed uni-formly in the composite.The interfaces between reinforcements of TiB,Nd₂O₃ and Ti matrix are clear without any interfacial reaction.The compress strength at room temperature and the tensile strength at elevated temperature of the TiB-Nd₂O₃-Ti composite have improved greatly.The fracture mechanism of the composite is affected by the microstructure of composites and testing temperature.