It was not until 770 BC that the State of Qin came into existence as one of the vassal states in western China. Later, it emerged as one of the seven most powerful states in China, assisted by Shang Yang's reform. King Ying Zheng (250 - 210 BC) embarked on a campaign of expansion. In the space of only ten years, Qin vanquished Han, Zhao, Wei, Chu and Qi one after the other, and united the whole of China in 221 BC.

Ying Zheng dreamed his power would be continues and unbroken. He called himself the First Emperor of Qin Dynasty - Qinshihuang, and his successors would be the second, third and so forth. Therefore, he is known historically as Qinshihuang.

Qinshihuang enacted a sweeping series of reforms to consolidate his power. The government was presided over by a prime minister. The Yushidafu supervised the bureaucracy, and the Taiwei was commander-in-chief of army. They were all appointed and removed by the emperor himself. The whole country was divided into 36 prefectures, later increased to more than 40, which were in turn divided into countries. The magistrates of the prefectures and countries were also directly appointed and removed by the emperor. In this way, the emperor could grasp the power to control all of the states. After the unification, Qinshihuang expanded the original Qin's laws and orders to the whole country resulting in a system of unified law.

In the Warring States Period, linear measures differed from state to state. Qinshishuang set fixed standard for length, volume and weight, which propelled the development of the economy. Qin Dynasty also issued a uniform currency. Round coins with a square hole in the middle were used all over China, and it promoted the economic communiction among different nationalities and areas, and set the pattern for the coins of later dynasties.

Qinshihuang also promulgated order to unify the charaters. The first reform of the characters resulted in the seal script - xiao zhuan. Then, the official script - lishu, a simplified version of the seal script, was devised. Today's regular script - kaishu developed from the official script. The standardization of Chinese charaters promoted communication and the culture.

In 213 BC, Qinshihuang adopted his prime minister, Li Si's advice that, all books, except for those on medicine and agriculture should be burned, in order to strengthen the regime's ideological control of people. To further guard against dissent, Emperor had 460 Confucian sholars buried alive in the second year. These two matters were called "Burning the books and burying the Confucian sholars."

Qinshihuang sent General Meng Tian to defeat the Huns - Xiongnu. To curb the incessant invasions of Hun nomads in the north, Qin Dynasty set about building the Great Wall by linking up already existing defensive walls that had been built by various states. In the south, Qinshihuang subdued Yue people and expanded the communication between defferent nationalities.

Qinshihuang ended the long divided situation, and estabished the first united multi-ethnic feudal country on Chinese soil. Qin's teritory, embracing over 20 million people, reached the pacific in the east, Longxi - west of Longshan Mountain, in the west, Great Wall in the north and South China Sea in the south.