In this paper, the modal flexibility curvature matrix FCM of composite was used to discuss the NDT composite materials, the natural frequency of the composite beam and shift values of each node are simulated by modal analysis. The damage of composite beam is detected by calculating the modal flexibility curvature matrix. According to the beam theory we put forward a new theory based on the modal flexibility curvature matrix to detect the damage of composite plate,namely longitudinal and transverse flexibility curvature matrix. The results show that for a single de鄄 lamination, longitudinal and transverse flexibility curvature mutation rates were 3. 6310 and 5. 4078 times respecting. For multiple delamination the longitudinal and transverse flexibility curvature mutation rates were 3. 5350,5. 9028 times at the small damage location. While at the big damage location,the longitudinal and transverse flexibility curva鄄 ture mutation rates were 5. 6803,10. 0109 times. Mutation position of flexibility curvature mutation coincides with the preset position. So longitudinal and horizontal flexibility curvature can determine the location and size of composite de鄄 lamination, and relatively speaking, longitudinal flexibility curvature works better than transverse flexibility curvature in damage detection.