The cluster-level architectural knowledge is the source to maintain sustainable competitive advantage of clusters. To develop the knowledge-based theory of clusters, the authors chose Dalian Software Park as the object of study, and work strictly according to scientific research process of the case study method. Firstly, they put forward the research questions and established the subject of the study according to the relevant literatures, and made a scientific study design to ensure the reliability and validity of the case study. Secondly, the authors collected research data and materials by the interview. Thirdly, the case analysis was carried out. Based on interview’s materials and secondary data analysis, they explored the content of the cluster-level architectural knowledge, discussed the roles played by different types of architectural knowledge in the development of industrial clusters and the impacts on the maintaining the competitive advantage of the clusters. The authors’ contribute by exploring the contents of the cluster-level architectural knowledge, which includes recognition of the strategies, convention, mutual benefit, industrial atmosphere, collective reputation, and institution.