It is important by in-situ synthesis method to fabricate magnesium matrix composites. In-situ synthesis of magnesium matrix composites reinforced with TiC ceramics by remelting and diluting method was studied in the paper. It was found through microstructure observation and XDR analysis that the fine reinforcements dispersed uniformly in magnesium matrix composites. It was indicated that the damping capacity of magnesium matrix composites was less than that of pure magnesium due to the addition of TiC, but the damping capacity of magnesium matrix composites can be enhanced by heat treatment.