Small and medium-sized enterprises (SMEs) play an irreplaceable role in promoting China's economic transformation and supply-side reform, but the reality is that China's SMEs are faced with extensive resource constraints. Therefore, it is extremely important to strengthen the ability to acquire and utilize external resources, especially complementary and critical external resources. On the basis of the classification of external resources, this study proposes the three ways of using external resources, which are respectively network embeddedness, cooperative cluster and user participation. Then, through the establishment of an SLIC analysis model, the study summarizes sharing mechanisms, learning mechanisms, integration mechanisms and collaborative mechanisms for SMEs to evolve external resources into their own growth ability. Logically, sharing mechanisms and collaborative mechanisms focus on the reasonable choice of external resources; learning mechanisms and integration mechanisms are intended to generate dynamic innovation capability and form sustainable competitive advantage. Finally, the study selects one technology-based SME, one manufacturing SME and one service SME respectively, with the intention to conduct a textual analysis of validation on their external resource utilization and capability evolution mechanisms.