The present invention relates to a system for measuring a sample pore using a computed tomography (CT) and a standard sample and to a method thereof, more particularly to a system for measuring a sample pore using a computed tomography (CT) and a standard sample and to a method thereof, wherein the number of pixels in the count range of a cross-sectional image of the measurement sample and the number of pixels corresponding to the gray level range of the pore are calculated with reference to the count range utilized in the cross-sectional image of the standard sample and the gray level range of the pore so as to accurately measure the porosity of the measurement sample after performing a CT scan of the standard sample and the measurement sample together using a CT scanner.