Since the provision of Permanent Affordable Housing in the early 1990’s, it is confronted with the need to strengthen its welfare service due to aging of its facilities and the declining welfare system for its tenants. In addition, the aging population of tenants is on the rise, increasing the group of tenants that are in need of care. The local social community center has entered into the community of permanent affordable housing and takes partial responsibility in the tenant’s social welfare. However, social community center is mainly responsible for providing welfare service to its local residents and thus limited in its ability to satisfy welfare service to tenants of permanent affordable housing. Therefore, it is required to renew the existing welfare system to better suit social demands of tenants according to its specific social group and the characteristics of housing complex. This study aims to propose methods that can strengthen welfare service and analyze the characteristics of welfare service by investigating the existing conditions of welfare system for the tenants in permanent affordable housing complex. For this purpose, this study presents with categories of service standards, by breaking down and codifying welfare service and propose applicable mixed-use service in pre-existing permanent affordable housing.