This book investigates the relationship between social capital and loneliness of older adults living in urban China during the COVID-19 outbreak period. It also tested the mediation role of community-based cognitive social capital on the relationship between community-based structural social capital and loneliness of older urban Chinese adults. This book targets at a broad audience with knowledge in social gerontology and social work with older adults. It will appeal to academic researchers, undergraduate and graduate students, policymakers, and social workers who have interests in social capital and mental well-being in later life, and the impacts of COVID-19 on the well-being of older adults.