Generally, wear is one of the main failure mechanisms for mold steel. The heavy financial loss will often occur if molds are out of service due to their hard manufacturing process and high cost of metal materials. Therefore, mold repairing is urgent and critical if they fail to function. Ni-matrix wear resistant composited layers reinforced by TiC generated from in situ plasma spray welding NiCrBSi+Ti powders were prepared. The analysis instruments of OM, SEM, XRD and EDS were used to study the microstructural characterization, phase identification and chemical compositions of the layers. And the microhardness and wear resistance were tested using Vickers hardness tester and abrasion tester, respectively. The investigations demonstrated that the layers were mainly composed of basic phases (γ-Ni+β₁-Ni₃Si) with eutectic features and hypereutectoid (α-Fe+FeNi₃) structures, in which hard phases M₇C₃ and M₂₃C₆ were embedded in the matrix. The phase CrB was distributed uniformly in the layers. One part of TiC generated from in situ reaction acted as the nucleation of the chromium compounds precipitates M₇C₃ and M₂₃C₆. The other part of TiC was also distributed in the base with the fine particles (<1 μm) and even bigger size (>1 μm). Ti percentage rising, the microstructures of plasma spray welding layers were refined and the phase M₂₃C₆ increased while M₇C₃ decreased. When the Ti addition reached 6%, the layers had better performance with microhardness of 800 HV_0.5. The wear mass loss of layers was 14.5 mg, which were more than 2 times of NiCrBSi layer.