<p> This paper discusses house types and their transformation of Haikou of Hainan (China). Haikou as a port city is one of the hometown of overseas Chinese in Southeast Asia, and as a famous historical and cultural city in China, has changed greatly in recent year. This paper first makes an analysis on the typology of houses, and then discusses the relationships between the different types to reveal their transformation processes.</p><p> The inspecting scope of this paper is the old city (Suocheng) of Haikou, which was a defensive city of Fucheng before the Qing dynasty, In the late Qing dynasty, due to the development of coastal trade, the center of the city moved from Fucheng to Suocheng. So far, the city has maintained a good urban texture in the late Qing dynasty.</p><p> Nowadays, the city is composed of 8 communities, the main public service facilities are evenly distributed, and the two large markets are concentrated in Zhenlong community. Many commercial shops are located in Boai road, Zhongshan road and Xinmin road. The biggest change in urban tissues space is in the north of Zhongshan road. In 2016, the urban development of Zhongshan road saw the Qilou reconstruction on both sides. With the development of tourism, lot of Qilou were demolished, and the current vacant land is used as a parking lot for sightseeing.</p><p> Courtyard House style is considered to be the residential style brought by immigrants from Fujian and Guangdong, with the largest number of three-span forms. Different from the quadrangle dwellings in the north, Haikou quadrangle dwellings have no "wing rooms" on both sides of the courtyard, and the structure is mainly lintel construction, and the first hall has no hypostyle column. The existing quadrangle dwellings in Haikou are very few, just over than 20 buildings, and scatter in the urban area. Arcades can be divided into four basic types from A to D, mainly distributed in Zhongshan road, Changdi road, Boai road and Jiefang road.</p><p> The evolution of Siheyuan is mainly reflected in two pattern of division and expansion. The division is mainly carried out in the direction of north and south with courtyard as the unit for property rights. The expansion is mainly to add a row of quadrangle dwellings or a row of Hucuo (auxiliary houses) horizontally. In addition, as a result of the increase of the living population, the function space of toilet or kitchen usually was added on the one sides of the courtyard to appropriately increase the use space. In the case of sufficient homestead, there are also examples of demolishing the original quadrangle dwellings and rebuilding the brick - concrete house. The evolution of the Qilou has three main modes: indoor courtyard, adding stairs and the position of stairs. At the same time, a multi-story and rental housing pattern had emerged.</p><p> The origin of Qilou(arcade) is usually considered to be a reverse import from Singapore. In 1849, the only earliest one Qilou building appeared in Haikou, which was not built in a unified plan. The planned construction of arcades began in the 1920s. The Qilou building on Xinmin road is also not planned for unified construction. The Siheyuan along the street are used as a shop, and the arcade is added outside which only happened in Haikou.</p>