Judgment needs to be made based on specific circumstances. Old linen is a traditional textile material with rough texture and tough texture. In the Song Dynasty, old linen cloth was widely used to make clothing, tents and other daily necessities, so some people also used it to create calligraphy works. Because the texture of old linen cloth is thicker and difficult to preserve, the number of old linen calligraphy works from the Song Dynasty that have been handed down is small. Therefore, it is necessary to make a comprehensive judgment on whether the old linen calligraphy works of the Song Dynasty are authentic.