The Hac Sa Site in Coloane, Macao, has been excavated four times; in 1973, 1977, 1985 and 1995 respectively. The prehistoric pottery on display were all unearthed in 1985, apart from one painted pottery dish with foot-rim which was found in 1977.

The archaeological excavation at the Hac Sa Site in 1985 discovered the upper and lower cultural layers and the pottery unearthed from the different layers actually belonged to two different stages. According to the carbon-14 dating system and the method of comparison study, the lower layer can be traced back to 6,000 years ago, which was the early stage of the Middle Neolithic era. The upper layer, however, was formed between 5,500 and 4,500 years ago, which was the late stage of the Middle Neolithic era.