Abstract: Industrial CT can effectively detect the parts in shape and appearance as an advanced nondestructive test method. A series of industrial CT images can be got after the part is scanned by industrial CT equipment. The industrial CT image is binary-coded, so the target and background are separated. Then the outer contour and inner contour are identified by contour tracking and the data of the outer contour and inner contour are fitted as spline curves. Finally, virtual measurements are used to get the dimensions of the outer contour and inner contour along the x direction, the y direction and the arbitrary direction.