The history of Haikou originates from Han Dynasty. In 110B.C. (the first year of Western Han Dynasty), General Lu Bode of Fubo conquered Baiyue, and set two prefectures-Zhuya and Zhan'er-and 16 counties in Hainan. Haikou was under Zhuyadaimao County. In Tang Dynasty, Haikou became a port of Qiongzhou, and it was the transportation hub to the mainland.In Song Dynasty, in order to consolidate the frontier, Haikoupu was established, hence the name. In 1858 (the eighth year of Emperor Xianfeng), Haikou was opened up to be a trading port, the name was changed into Qiongzhou kou.

Haikou is at the northern edge of the torrid zone, and it belongs to the monsoon tropical zone. The annual temperature is 23.8℃ on average. Summer is long and winter is short. There is no obvious change in different seasons. Daytime is long, so it is rich in sunlight. The rainfall here is plentiful, and the wind is a little bit strong. Every year, from April to October is the active period of tropical storm and typhoon, and most of them occurred between August and September. May to October is the rainy season, and most of the rainfall comes in September, and the average precipitation is 300.7mm. July and august are the hottest months with the average temperature about 29℃, and January, the coldest, with the temperature about 17.2℃. It is suitable for tourism in all seasons, and the golden period is from October to the next April. When the north is covered with white snow, Haikou is still in green.

Among the ancient remains and tourist sites are Wugong Temple reputed to be the "first building under the heaven", the admirable Qiongtai Academy of Classical Learning, the Hairui Tomb, the Qiujun Tomb, and the like.