Structural holes have great impacts on product innovation, but the specific mechanism of action is still in mystery. Based on the perspective of knowledge search and transfer, this paper proposed and validated the conceptual model of the influence of structural holes on productive innovation performance. Results show that there is inverted U-shape relationship between structural holes and product innovation. In addition, although knowledge search and transfer both have positive effects on product innovation performance, structural holes is conducive to knowledge search but not for knowledge transfer. The different roles played by structural holes in this process are the reasons for the formation of inverted U-shape relationship between structural holes and product innovation performance. The conclusion of this study provides theoretical guidance for enterprises to have more effective use structural holes.