In-situ processing of Al alloy reinforced with TiC composites was investigated by thermal plasma. Thermodynamic analyses were made for predicting conditions of synthesis and recovery ratio of TiC. A 3D mathematic model was developed for describing temperature profile and velocity distribution within the reactor. The model is applied to predict feeding rate, design in situ processing system of composites. Results showed that the basic understanding of thermodynamic properties of TiC, temperature profile and velocity distribution within reactor and vapor saturation of TiC is essential for the synthesis of composites. The experimental results showed that pure TiC compound can be obtained and TiC product particles size obtained was around 100nm. Microscopic analyses showed that the size of the TiC particles produced using Ti as starting materials is less than that using FeTiO3.