In the social background of population ageing, this paper addressed the issue of social isolation and loneliness. Reflecting on the current design for social connectedness. We advocate a positive perspective to older people and consider design as mediation for social connection. Practice cases and research show the potential of design mediation connection, however, there is a lack of summarized knowledge of how to design for mediation. This paper aims to answer the research question-How does design as mediation facilitate social connection? This question was answered from two aspects. One focused on the form or features as regards to the design as a result, the other is reflecting design as an ideating process. This research follows a Research through Design (RtD) approach. A design project was launched in a design course for design students. Research materials, including the design process and design outcome, were documented and reflected. As a result, the design elements for enhancing social connection was clarified and conceptualized. It includes five categories from abstract to concrete level, namely role, partnership, encounter, facility and trigger. Design strategies were also concluded according to the five elements. The paper also proposed an ideation process of designing for social connection by linking the design elements with the ideation activities. This research criticized viewing socializing as a functional activity and advocated a new perspective of design as mediation for social connection among older people. The results provided practice guidance and reference for designers in designing intervention for social connection.