Cu-TiB2 composite has been manufactured by spray forming process. The microstructures of over-sprayed powder, spray-formed billet, and extruded rod have been characterized by optical microscopy and x-ray dif­fractometry. The tensile strength of extruded rod was measured by tensile testing. TiB2 particles were form­ed in a Cu melt of 1500℃ by chemical reaction between Ti and B. The TiB2 volume fraction within the spray-formed billet varied by the density difference between TiB2 and Cu melt. The strengthening of Cu-­TiB2 alloy was well described by dislocation pile-up model. The results indicate that yielding of this com­posite was subject to reinforced particle fracture by local stress concentrations caused by dislocation pile-up between obstacles. Reinforcement fracture also has an effect to decrease the work hardening rate with the in­crease of reinforcement volume fraction during plastic deformation. We believed that this is because of the strengthening loss due to the increase of fractured particles with increasing TiB2 volume fraction.