In this study, based on an interview survey of 28 courtyard houses' owners and managers about the renovations, constructions and households change since the houses construction, we tried to reproduce the occurence process of collective living and living space formation. The constructions and renovations in the houses are almost based on the change of the owner family's life stage. In many houses, with the decrease of the number of relatives and parents, some rooms are rented to other households without kinship, but very few new construction are held for them. We also defined the collective living as the living of more than 2 households in the same courtyard house with different "GWA"(kitchen range). Based on that we made the model of collective living and living space formation in 6 patterns. The process in each model can be divided into 4 steps.