Abstract: Pot experiments were carried out to study the effect of water deficit on vascular bundle system of rachis in wheat during heading stage. The results showed that the number and the area of macro-vascular bundle and small-vascular bundle of rachis and the diameter of vessel and the area of phloem decreased from base to top, but the decreased rate differed with the change of the kind of vascular bundle and position of rachis. Compared with normal water treatment, the number and the area of macro-vascular bundle and small-vascular bundle of rachis and the diameter of vessel and the area of phloem decreased under moderate water deficit, while it decreased obviously under the severe water deficit. It showed that the vascular bundle system of rachis in wheat changed apparently under water deficit.