In Bamako, the urbanization and the rapid population growth is changing the scale and the density of conventional courtyard houses. The high density results the transition of conventional houses from single-traditional-family into multi-family houses. For Bamako, the existing collective living in courtyard houses which is more coherent with and interresponsive to the life style, is an important living style. In this paper, based on an observation survey on residents activities in the courtyard, we attempt to clarify the problems related to high density living and its influences on the courtyard.