Carbon fiber reinforced polymer (CFRP) is widely used for making leaf joint and cartridge receiver with the development of material science and structural mechanics. The main kind of flaw is delamination, but this type of flaw can not be tested easily by using tradition method. In order to promoting the product quality, pulse theography is developing and becoming perfect. But the test sensitivity of pulse theography can not be definited exactly, in order to solve this problem, pulse thergraphy method is used for testing artifical parts with different delamination flaws. Pulse theography method can find and locate the delamination flaw in CFRP, can measure the size and depth of the flaw. When the percentage of wide and depth is lower than 3, the test sensitivity is lower than 10%, and the sensitivity is becoming low as the size become small and the depth become deep.