Ti6Al4V powder added TiB₂ particles with a mass fraction of 0%~5% was melted using selective laser melting to produce the in-situ TiB/Ti6Al4V composites to study the forming properties, microstructure evolution, and mechanical properties of samples with different TiB₂ additions. When the mass fraction of TiB₂ added was 1%, the α′-Ti in the microstructure of the sample gradually disappeared, and a dispersedly distributed unit cell like TiB was observed. Further addition of TiB₂ caused the strengthening method of the material to evolve from dispersion strengthening to whisker strengthening. Simultaneously, TiB in the grain boundary was enriched to form a dendritic structure and a network structure. The in-situ TiB as a nucleation point can remarkably enhance the hardness and friction performances of the TiB/Ti6Al4V sample under the action of fine grain strengthening, solid solution strengthening, and whisker strengthening. As a result, the microhardness of the sample increased from (336.8±6.64) HV to (498.07±12.56) HV, and the wear mechanism of the sample changed from adhesive wear to abrasive wear. When the mass fraction of TiB₂ added was 1%, better wear performance was obtained.