The characteristics of fiber-reinforced thermoplastics depend on the quantity and shape of fibers. The fiber-matrix separation and fiber orientation are caused by the flow during a molding process. Then, the product tends to be nonhomogeneous and anisotropic. Hence, it is very important to clarify the relations between separation-orientation and molding conditions. In this paper, we propose the measurement method which is called image intensity method for fiber orientation distribution by image processing. In order to examine the accuracy of intersection counting and image intensity methods, the fiber orientation of simulation figure is measured using image processing. The image intensity method is rather accurate compared with the intersection counting method.