The last northern expedition in East Jin and the South dynasties took place during Taijian Reign when Emperor Xuan of Chen Dynasty was in power.With a political strategy of allying with North Zhou while attacking North Qi,he firstly dominated the region between the Yangtze River and the Huaihe River,then fought at Zhou to get the land between the Huanghe River and the Huaihe River.In terms of the relation between occupying the military points at the confrontation between the North and the South dynasties and the security of the land south of the Yangtze River,this expedition had both the aims of strategic defence and offensive.Founded at the end of the South Dynasty,Chen Dynasty was inferior to the North Dynasty at both economics and armaments,however,the short-sighted Emperor Xuan didn't realize the situation,which inevitably led to the final failure of the expedition.Owing to the faulty choice of the strategy"allying with North Zhou while attacking North Qi",the northern expedition failed when the North Zhou was unifying the whole North side though it did win several battles when North Zhou and North Qi was in war.The failure of the expedition not only made Chen Dynasty lose its armies abroad and the region between the Huaihe River and the Sishui River,but also influenced the historical progress of the unification between the North and the South sides.