The capital city of Beijing is a thriving background for a research due to its ancient history and the related layering of urban practices accumulated that still display a role in urban morphology of the contemporary city. Taking the city of Beijing as a starting point for the research, the aim is to study the socio-cultural background that drove to the formation of the hutong system as well as the siheyuan, the courtyard houses. Thereafter, the study of the leading forces that in the 20th century lead to dramatic changes, modifying the urban fabric in the Old City of Beijing. In this background the siheyuan and hutongs, suffered of an undisputable densification during the process of gentrification and demolition.