The thermal shock behavior of TiB2- Cu composite by combustion synthesis was investigated using plasma arc heating and numerical simulation. The transient temperalure field and thermal stress fields affected by inhomogeneous boundary conditions of heat transfer in high temperature were simulated and analyzed based on the thermal physical data with ANSYS commercial software. The results reveal that the maximum compression stresses are generated at center of sample and decreased along radius. The compression stresses transform to tensile stresses when the arc beam gets across the heating area, and the largest tensile stress takes place in the edge of the specimen. The crack may initiate in the edge of the sample, and then properly propagates to the position of center in the direction of radius. The experiment of plasma arc heating also favor and approve the rationality nf theoretical model.