In this study, the in-situ synthesized TiB/Ti-6Al-4Vceramic-matrix nanocomposites with greatly enhanced hardness and wear resistant property have been prepared via selective laser melting (SLM) using a simple mixture of microsized Ti-6Al-4V and TiB2 powders. In order to provide a valuable reference for fabricating TiBM-6Al-4V parts with metallographic features, effects of reinforcement content on microstructure and mechanical properties have been systematically investigated. It is found that during SLM process, the additive particles TiB2 are totally transformed into need-like nanoscaled TiB phase, and the microstructure of composites is composed of mutual parallel strips architecture with TiB rich in some regions but lean in the other regions. The SLM-producedTiB/Ti-6Al-4 V composites exhibit superior nanohardness of 6.0 GPa, which is much higher than its traditional sintering counterpart. Moreover, the in-site synthesized TiB reinforcement can remarkably improve in the wear resistance properties, the wear loss of TiB-free sample is approximately 2 times than that of the sample with 3 wt% TiB2. (C) 2018 Elsevier B.V. All rights reserved.