Yuan Shao extended his power to the north of the Yellow River, while in further south, between the Yellow River and the Huai River, there was a tense and vicious conflict between Yuan Shu, Cao Cao, and Tao Qian, the Governor of Xu province, Lu Bu from the northwest and Liu Bei, a man of poor family who yet claimed descent from the rulers of former Han.
Yuan Shu was driven south to of the Huai River in 193, Tao Qian was destroyed in 194, and Liu Bei surrendered in 196.
袁术于公元193年兵败逃到河北（淮河以北），陶谦于次年被击败，刘备在196年投降曹操。Cao Cao’s power spread unprecedently, and by 198，when he captured Lu Bu and killed him, Cao Cao had no further rival in the southern part of the Yellow River area.
曹操的军队实力盛极一时，到198年曹操俘杀吕布后，在黄河流域已无人能敌。
In 196, Cao Cao forced Emperior Xian to move his capital to Xuchang (in pres-' ent-day Henan Province), took advantage of ruling in the emperor ’ s name and continued to project his he justified his actions as a loyal minister of Han.
公元196年，曹操又将洛阳的献帝迎至许昌，挟天子以令诸侯，在政治上得到了优势。During this period, the development of agriculture was heavily hampered and there were prevailing famines, therefore food supply was fatal for warlords. The cases were countless that the warlords were self-defeated for lacking sufficient food supply instead of being destroyed in the battle.
这一时期，社会生产遭受严重破坏，出现大饥荒。粮食供应成为各军事军队最大的问题，因军粮不足而无敌自破者不可胜数。In the same year, Cao Cao accepted a land reclamation system，an advice proposed by Zao Di，one of his subord卜 nate. According to this system, destitute peasants placed under military officers were organized into civilian colonies to work in the land while soldiers, when not fighting, were encouraged to grow crops in military colonies. This system yielded with great harvest and excellent results.
建安元年，曹操采纳部下枣祇等人的建议，在许下募民屯田，当年即大见成效，得谷百万斛。Then the system was spread all over the country which effectively settled the problem of food supply of the army. Meanwhile, Cao Cao implemented other policies such as subsiding small owner-peasant, transferring people to farm on the deserted farmland in war zones, developing the irrigating system and recovering the growing of agriculture.
于是曹操命令在各州郡设置田官，兴办屯田。屯田有效地解决了曹操军队的粮食问题，在兴置屯田的同时，他采取各种措施，扶植自耕农经济。针对当时人口流失，田地荒芜的情况，曹操先后采取招怀流民、迁徙人口、兴修水利、恢复农业生产等措施。All these practices enhanced the agricultural development and enriched the national reserve.
通过以上措施，曹操统治区的农业生产迅速恢复。这是其在经济上的一大成功。Since the year 198, after taking protection and control of Emperor Xian, Cao Cao started his plan of crushing other warlords and united the northern part of China.
从建安二年起，曹操利用他“挟天子以令诸侯”的政治优势，东征西讨，开始了他翦灭群雄，统一北方的战争。In the summer of 200, armed with 100 000 skillful land armies and about 10 000 cavalries,Yuan Shao marched south to fight with Cao Cao killed Yuan Shao ’s two fierce warriors Yan Liang and Wen Chou in succession and stayed in the small city of Guan Du, south of the Yellow River(Zhongmou county, Henan Province) where Yuan Shao and Cao Cao met in a long-drawn campaign.
公元200年夏，袁绍挑选10万精锐步兵，骑兵万余，南下与曹操争锋，曹操先后击杀袁绍勇将颜良、文丑后勒兵官渡（今河南中牟县）；袁绍兵力远远超过曹操, 但交战一月后袁绍无法取胜。Cao Cao ’ s forces were heavily outnumbered, but they held their defence for more than a month, then a fortunate raid against the enemy ’ s supply lines in Wuchao broke the morale of Yuan Shao, s forces and the chief general Zhang He and Gao Lan surrendered. Cao Cao launched a counterattack, killed ten thousands and captured about 70 000 of the enemies and drove them in disorder to the north. Two years later, Yuan Shao died, his two sons fought against each other over the inheritance，and Cao Cao took advantage of the confusion.
后曹操放火烧掉袁绍屯放于乌巢的军粮等军用物资，袁绍大将张郃、高览投降曹操，袁军士气全无，曹操乘机发动大反攻,杀万余，俘虏7万余。袁军仓皇北逃，其后袁绍一蹶不振，两年后，袁绍病死，二子争位，曹操加以利用。In 207, after a brilliant campaign at Wuwan，Cao Cao cleared off Yuan Shao’ s remaining forces, established control o-ver all the Yellow plain and became the most powerful military lords in north of China.
公元207年,曹操远征乌丸，出其不意，大胜，平定了北方，一举成为北方最强的军事集团。