To provide the test method for thermal shock resistance of throat insert material in rocket motor design, an experimental method with a SRM of scale down was developed to simulate the thermal load of full-size rocket motor’s throat insert. The test guaranteed the consistency of propellant、chamber pressure 、rate of ignition pressurization and the contour of the surface of throat insert with full-size rocket motor, and make a compromise of condition of throat insert at the same time. This method had well reappearance of the fracture failure of throat insert of a full-size rocket motor, which proved the feasibility of the test method to a certain extent. A comparison test for thermal shock resistance of two different composite materials was carried out. The experimental results indicate that two reserve C/C composite materials had good thermal shock resistance than three directions woven C/C composite material which used in the motor of failure, and the performance of carbon fabric pierced C/C composite material was better than no woven fabric pierced C/C composite material in some sort.