Abstract: Knowledge is the most important source of a company's competitive advantage, but it is unclear how companies use their knowledge base to find the optimal knowledge acquisition strategy. This study examines the threshold effect of four types of knowledge acquisition methods (internal R&D, technology purchase, cooperative R&D, and talent introduction) on innovation at the depth and breadth of the knowledge base. Based on the empirical analysis of 172 biomedical companies, the threshold effect of the depth and breadth of the knowledge base on the impact of knowledge acquisition on innovation performance has been confirmed. First, as the breadth of knowledge increases, independent R&D and technology purchase have gradually enhanced the promotion of innovation. However, R&D cooperation and talent introduction have an inverted U-shaped relationship to innovation. Secondly, with the deepening of the knowledge, internal R&D and talent introduction have an inverted U-shaped relationship to innovation performance, and the role of technology purchase and R&D cooperation in promoting innovation performance has gradually strengthened. Finally, based on the dual attributes of the knowledge base, companies are divided into five categories: knowledge-poor, specific, active, ideal, and general, and a checkered model of optimal knowledge acquisition combination strategy is developed.