The Second Opium War ( 第二次鸦片战争 ) was a war of the United Kingdom, the United States of America and France against the Qing Dynasty ( 清朝 ) of China from 1856 to 1860. The war may be viewed as a continuation of the First Opium War ( 1839 - 1842 ), thus the title of the Second Opium War .

The 1850s saw the rapid growth of imperialism. Some shared goals of the western powers were to expand their overseas markets and establish new ports of call. The French Treaty of Huangpu ( 黄埔条约 ) and the American Wangxia Treaty ( 望厦条约 ) both contained clauses allowing renegotiation of the treaties after twelve years. In an effort to expand their privileges in China, Britain demanded the Qing authorities renegotiate the Treaty of Nanjing ( 南京条约 ) in 1854 citing their most favored nation status. The British demands included opening all of China for British merchants, legalizing the opium trade, exempting foreign imports from internal transit duties, suppression of piracy, regulation of the coolie trade, permission for a British ambassador to reside in Beijing and for the English-language version of all Treaties to take precedence over the Chinese. The Qing court rejected the revision demands from Britain , France and the USA .

On October 8, 1856, Qing officials boarded the Arrow ( 亚罗号 ) , a Chinese-owned ship that had been registered in Hong Kong and was suspected of piracy and smuggling. Twelve Chinese subjects were arrested and imprisoned. This has come to be known as the "Arrow Incident". The British officials in Guangzhou demanded the release of the sailors claiming that because the ship had recently been British-registered it was protected under the Unequal Treaties. Only when this was shown to be a weak argument did the British insist that the Arrow had been flying a British ensign and that the Qing soldiers had insulted the flag. Faced with fighting the Taiping Rebellion ( 太平天国运动 ) the Qing government was in no position to resist the West militarily.

Although the British were delayed by the Indian Mutiny, they responded to the "Arrow Incident" in 1857 and attacked Guangzhou from the Pearl River . Ye Mingshen ( 叶名琛 ) , the then governor of Guangdong and Guangxi provinces ordered a non-resistance command to all of the Chinese soldiers on the forts. After taking the fort near Guangzhou with no effort, the British Army attacked Guangzhou . American warships, including Levant , bombed Guangzhou . The people in Guangzhou and soldiers launched a resistance against the invaders and forced them to retreat from Humen.

The British Parliament decided to seek redress from China based on the report about the "Arrow Incident" submitted by Harry Parkes, British Consul to Guangzhou . France , the USA and Russia received requests from Britain to form an alliance. France joined the British action against China , prompted by the execution of a French missionary, Father August Chapdelaine, by Chinese local authorities in Guangxi province. The USA and Russia sent envoys to Hong Kong to offer help to the British and French, though in the end they sent no military aid.

The British and the French joined forces under Admiral Sir Michael Seymour. The British army led by Lord Elgin, and the French army led by Gros,attacked and occupied Guangzhou in late 1857. Ye Mingshen was captured, and Bo-gui, the governor of Guangdong , surrendered. A joint committee of the Alliance was formed. Bo-gui remained at his original post to maintain order on behalf of the aggressors. The British-French Alliance maintained control of Guangzhou for nearly four years. The coalition then cruised north to briefly capture the Taku forts near Tianjin ( 天津 ) in May 1858 .

In 1859, after China refused to allow the esablishment of embassies in Beijing as agreed to by the Treaty of Tianjin ( 天津条约 ) , a naval force under the command of Admiral Sir James Hope shelled the forts guarding the mouth of the Peiho river. It was damaged and withdrew under the cover of fire from a naval squadron commanded by Commodore Josiah Tattnall .

In 1860, an Anglo-French force gathered at Hong Kong and then carried out a landing at Pei Tang on August 3, and a successful assault on the Taku Forts on August 21. On September 26, the force arrived at Beijing and had captured the city by October 6. Appointing his brother, Prince Gong, to be in charge of negotiations, Emperor Xianfeng ( 咸丰帝 ) fled to the Summer Palace in Chengde. British-French troops in Beijing set the Summer Palace and the Old Summer Palace on fire following several days of looting. The Old Summer Palace was totally destroyed. Beijing was not occupied however the troops remained outside the city itself.

After the Xianfeng emperor and his entourage fled Peking, the June 1858 Treaty of Tianjin was finally ratified by the emperor's brother Prince Gong in the Convention of Peking ( 北京条约 ) on October 18, 1860, bringing The Second Opium War to an end.