Real estate advertisement sale-agent (REASA) is the most characteristic in Taiwan real estate industry. REASA serves as a training platform for those who want to be a housing developer because its major business for housing developers is to provide services of market information, advertising strategies planning and marketing plan execution for housing developers. Under tactical intention, REASA management will arrange its resources efficiently to proactively transform its business into housing developers if the industry environment suits the conditions. After transformation, some REASAs succeeded but the others failed. The variation among those is worthy to be studied. This paper bases on REASAs¡¦ internal resources to explore the impact factors of REASA transforming into housing developer. This paper will go through 3 perspectives, namely business resources, core capability and competitive strategies to discuss what kind of business resources and core capability that REASA have and how those become competitive advantages. I will study 3 elements of business resources, core capability and competitive strategies that relied by REASA transforming into housing developer. After researching of 2 successfully transformed companies in Kaohsiung and interviewing 2 professionals, the conclusion is made as below, A. The core resources for REASA are: 1. Human resource; 2. Goodwill; 3. Organization resource. Moreover, invisible resource is more valuable than visible resource for REASA. B. The core resources for housing developer are: 1. Financial resource; 2. Land resource; 3. Human resource. The difference from REASA is that visible resource is more valuable than invisible resource for housing developer. C. Apart from operation management capability, the core capabilities for REASA are: 1. Research & Development; 2. Marketing; 3. Advertising executing. These 3 are the most important factors and comprehensive effect cannot be produced if one lacks. D. The core capabilities for housing developers are: 1. Management; 2. Research & Development; 3. Financial management; 4. Construction management. E. The core resources for transforming impact are: 1. Financial resource; 2. Relationship connection; 3. Human resource; 4. Economic resource. And the core capabilities for transforming impact are: 1. Operation management; 2. Research & Development; 3. Financial capability; 4. Human resource management. F. The correlation among core resources, core capabilities and competitive strategies are: Differential strategy is to emphasis more on Research & Development and Design capabilities; Low-cost strategy is to focus more on cost control and marketing capabilities; Focus strategy is to stress more on operational, Research & Development, Financial planning and Construction capabilities. Different resources and capabilities are utilized subject to different strategies in order to reach competitive advantages in the industry.