This study focus on the key factor of the urban renewal in resettlement housing in Taipei city. We pick up 2 success cases of urban renewal case in resettlement housing in order to find out the important factor. After the case studies of No.4 and 5 section of Shuiyuan Rd. resettlement housing and No.2 section of Wuxing St. resettlement housing, we propose important key factor for urban renewal in resettlement housing including: 1. Establishment of reasonable system of trust loan; 2. Promotion of the establishment of urban renewal association by local community; 3. Establishment of appropriate strategies of demolition and resettlement for existing households.