The Manchus retained the traditional imperial administration of the Ming dynasty. The conquerors required all Chinese males to wear the Manchu headdress of the queue (pigtail).

Through their conquests, the Manchus greatly extended the power of the Chinese Empire. In addition to Inner Mongolia and Manchuria, both originally under Manchu control, Outer Mongolia, Tibet, Taiwan, and Chinese Turkestan all became part of the Chinese Empire.

In the early 1800's, trade with the Western nations greatly increased, although officially confined to only one port, Guangzhou. Much of the trade was illegal, as the British and other Westerners profited by smuggling opium into China. The Manchu government attempted to stop the importation of the harmful drug; the result was the Opium War with Great Britain, 1839-42. China lost, and was forced to sign a treaty ceding Hong Kong to the British and opening four new ports to them. Within a few years these ports were opened to other foreigners.

From the 1830's to the early 1860's, China was beset by several revolts. The most serious was the Taiping Rebellion. In 1850, the rebel forces, or Taipings, defeated the imperial armies and took control of most of central China, making Nanjing their capital. The Manchus, with armies reorganized along Western lines, finally defeated the rebels in 1864.

Meanwhile, encroachment by foreign powers on China's sovereignty continued. In 1860 China opened more ports to foreigners as a result of losing a war to France and Great Britain. In the 1880's, China lost two of its tributary states: Annam to France, and Burma to Great Britain. After the Sino-Japanese War (1894-95), China ceded Taiwan and the Pescadores to Japan and renounced claims to Korea. In the late 1890's, the Western powers received additional concessions and territory.

Antiforeign sentiment in China was high in the late 1890's, and by mid-1900 a rebellion broke out. It was led by a secret society called the Boxers, whose aim was to drive all foreigners out of China. Many foreigners were massacred before Western and Japanese troops quelled the outbreak.

After the Boxer Rebellion most of the foreign powers in China accepted the Open Door Policy, a proposal put forth by the United States in 1899 that all nations be granted equal commercial opportunity in China. The Manchus, on their part, put into effect many reforms. They established a school system with Western-style education, which gradually replaced the traditional schooling. In 1905 the literary examinations for government service were abolished. Some Chinese, however, did not think the pace of reform was fast enough. They organized secret revolutionary groups and made several attempts to overthrow the government. A prominent revolutionary was Sun Yat-sen.