A method for measuring the volume fractions of component material of textile composite by using micro CT experiments was developed. This method can present global, local fiber and yarn volume fractions by micro CT images in different scales, and can also offer solutions to the difficult volume fractions measurement of component materials of some composites which cannot be measured directly by conventional physical experiments. An E-Glass/Epoxy textile composite was used to illustrate the feasibility and reasonability of the method by the comparisons of the measured values among ASTM D3171 Procedure G, scanning electron microscope and micro CT experiments. Corresponding image processing methods for the scanning electron microscope and micro CT images were used to acquire the accurate component material segmentations. The measurement of micro CT experiments can be widely applied to measure the volume fractions of component materials of composite.