Abstract: Anatomical studies were conducted on the culms of two types of Dendrocalamus sinicus.The Microscopic observation and Systematic analysis were made to investigate the morphology of the vascular bundles,vessels and fiber.The result showed:the vascular bundles of Dendrocalamus sinicus belonged to the type of broken type and double-broken type.The latter had a primitive character only at the base of culms.The length of vascular bundles varied from 0.17 to 1.77 mm,the average was 0.68 mm.Its width was 0.14 mm to 1.08 mm,and the average was 0.67mm.The ratio of length and width was 0.29 to 3.00,and the average was 1.03.The maximum number of vascular bundles per square millimeter across the bamboo culm wall was 17.5.The minimum one was 1,and the average was 5.98.The mo rp ho lo gy of vascular bundles varied on the different positions of culm.The study on variation analysis of variance indicated that the axis way and across way of culms had higher influence on the vascular bundles morphology than that in ages.The length of vessels and fiber of Dendrocalamus sinicus became shorter when deformed internodes happened.