The military force consisted of the Eight Banners and Beiyang army as well as 40,000 soldiers, but many soldiers were already lost at the time of the battle of the castle, having been killed in battle or having lost the will to fight and fled when being defeated by the allied forces invading from Tianjin.
北京には八旗や北洋軍ほかおよそ4万人強の兵力が集められたが、さきに天津から進攻する連合軍との戦いで敗れ、戦死あるいは戦意喪失による逃亡によって城攻防戦の際にはすでに多くの兵が失われていた。