Abstract: Northern nomadic invasion on the Central Plains dynasty usually occurred in the fall, so the Northern Song Dynasty, considering the historical reasons and their own situation on the basis of each fall, implemented the key defense of the border. The court of Song Dynasty discussed anti-autumn matters in June and July each year, and deployed in August. The main anti-autumn forces were imperial guards to ban the main, and all kinds of village soldiers supplemented. The anti-autumn army logistics supply was led by the state, and undertook along the edge of the specific governments. In order to strengthen the anti-autumn reserve, the Song Dynasty built pond in Hebei region, and extensively constructed mountain fortress in the Shannxi area. In addition, the Northern Song Dynasty further improved the anti-autumn system by training the army, rewarding military service, regulating the Generals. The implementation of anti-autumn policy, effectively reflects the key time and the specific contents of the annual routine national defense of the court, also makes anti-autumn concept deeply rooted in the hearts of the people, to promote the Song Dynasty emperor and ministers to maintain necessary alert on the national military under the atmosphere of “Chongwenyiwu”.

Key words: Northern Song Dynasty, national defense, autumn defense