In this study,filed experiment was conducted to explore the change of vascular bundle structure in first internode of super hybrid rice during grain filling stage and its relationship with yield and its components under different nitrogen(N) application rate treatments［0(N0) ，150(N10) ，210(N14) ，300 (N20) ，390(N26) ，450(N30) kg/ha］，so as to provide theoretical basis for the physiological mechanism study of increasing yield of super hybrid rice.The results showed that the application of N could change vascular bundle structure in first internode of super hybrid rice.With the increase of N application rate， the number，area and total area of small and large vascular bundles of various varieties increased first and then decreased，which were the best under the N application rate of 210 kg/ha.The number，area and total area of large and small vascular bundles in first internode of super hybrid rice were significantly negatively correlated with the number of effective panicles(except the number of large and small vascular bundles) and 1 000-grain weight，but significantly positively correlated with the grain number per panicle，seed setting rate(except the number and area of small vascular bundle) and yield(except the area of small vascular bundle) .In conclusion，reasonable application of N could affect the ability of “flow”by changing the structure of vascular bundle，which was mainly reflected in improving the grain number per panicle and seed setting rate and then increasing the yield of super hybrid rice，and the N application rate of 210 kg/ha was the best．