The evidence of the historical development of the Songkla Lake Basin (covering Nakhon Si Thammarat Province, Songkhla Province, and Pattalung Province) has been found since the 5th BE, and clearly noticed during the 12-13th BE as the port of Srivijaya Kingdom. Then in 16th BE, pieces of evidence of relationship with the Song Dynasty of China were found. During the 17-18th BE, Nakhon Si Thammarat played its role as the centre of Tambalinga Kingdom. In the 20th BE, many cities in the South were under the control of Ayudhya and Rattanakosin, the capitals, respectively. Political control and Buddhism were clearly seen. For economic circumstance, people lived their lives mainly on farming and doing agricultural activities. Due to the fact that farming needed much labour, people lived altogether. Communities expanded and temples were their centre. For the study of the floor plan of Buddhism vernacular architecture, it was found that the compositions and forms were similar to those found in the Chao Phraya Basin during Ayudhya and Rattanakosin period because of influence and relationship in terms of politics and Buddhism. However, due to its geographical aspects, the South has witnessed and experienced other cultures. This affected forms of architecture although the South has mainly been inspired by the Central Region, along with its own transformation and evolution. The study also found that the floor plan of temples is similar to that of the Central Region, for example Ubosot and the main Chedi were the main compositions, found in old temples, while Bua or small Chedi, keeping ancestors’ relics, were found in small temples, both outdoor or in the pavilion. The pavilions for miscellaneous purposes, because of the monsoon, were also found in the floor plan. In addition, vernacular architecture for shadow puppet theatre was also found generally.