Three non-destructive test (NDT) methods were used to detect the two dimensional C/SiC specimens after low velocity impact (LVI) of various energies. The damage areas characterized by these methods were very different. Both ultrasonic and thermographic images reveal the LVI damages, while X ray is non-sensitive to the interior damage. However, small delaminations were not found by thermography and accurate judgment depends on the experience and the resolution of the infrared camera. And the result acquired from the higher frequency transducer was very confused because of the inherent defects. It is suggested that using both ultrasonic C-scan and thermography to evaluate the LVI damage of C/SiC. It is also suggested using the transducer of low frequency to perform the ultrasonic C-scan.