Woolyang(月梁) is a beam which whole shape is curved like a so-called moon(月). According to the 《Yeongjobeosig(營造法 式)》, In the case of beams installed under the ceiling of a wooden building, it is used by manufacturing them in Woolyang(月梁) for maximum visual decorative effects as the shape is exposed. In order to achieve the end of a beam that is manufacturing in Woolyang(月梁), it is important to process it in a suitable size and shape for a given situation to achieve a combination with other members around it. However, in the 營造法式, the standard of production of the Woolyang(月梁) is divided into Myeongbog(明栿), Chagyeon(箚牽), Pyeonglyang(平梁), and the height of each beam head is divided into 21分°, 15分°, 25分°, but it is not possible to look at any more specific reference. In this paper, try to consider the principle of Woolyang(月梁) manufacturing and its normative contents which were indirectly proposed in the 《Yeongjobeosig(營造法式)》.