Abstract: As an important factor for the organization to achieve and maintain long-term success, the sustainable competitive advantage has been widely valued by the academic and theoretical field, but the existing researches lack the integration perspective of internal and external factors to explore the formation mechanism of sustainable competitive advantage. Hence, based on the resource-based theory, this research establishes a model to investigate the impact of boundary-spanning search on sustainable competitive advantage and examine the mediation role of knowledge integration from the viewpoint of external knowledge acquisition and internal knowledge integration. With advanced manufacturing firms as the research objects, empirical study is conducted based on 316 effective questionnaires. The results show that proactive boundary-spanning search and following boundary-spanning search have inverted U-shaped influence on sustainable competitive advantage; and both types of boundary-spanning search have positive influence on knowledge integration. Moreover, knowledge integration has an inverted U-shaped effect on sustainable competitive advantage. The results further indicate that the effects of proactive boundary-spanning search and following boundary-spanning search on sustainable competitive advantage are partially mediated by knowledge integration.