Ceramic matrix composite is increasingly wide used because of many advantages such as high temperature resistance, corrosion resistance and high specific strength. However, various defects can be created in the production because of the limitation of raw material and manufacturing process, and those defects can be detected by ultrasonic inspection, CT, infrared thermal imaging, X-ray inspection and so on. Based on the micro-focus CT system, this article investigates the testing method of adjustment sheet parts made of ceramic based composite. It is verified that micro-focus CT system is capable of detecting sub-millimeter holes in the production, and the result of measurement is accuracy. Besides, the micro-focus CT can obtain clear images of defects such as inclusion, crack and wire break-off. Furthermore, this CT system can achieve the calculation of porosity rate in the material.