Based on the theory of positive organizational behavior and knowledge creation，taking 243 enterprise personnel as the research object，hierarchical regression analysis and Bootstrap sampling inspection method are used to discuss the mechanism of the impact of employee psychological capital on radical innovation performance，and the mediating role of tacit knowledge acquisition in the process is analyzed. The results show as follows. The psychological capital has a significant positive impact on the company’s radical innovation performance；tacit knowledge acquisition partially mediates the relationship between psychological capital and radical innovation performance. Among them，skill‐based tacit knowledge acquisition partially mediates the influence relationship between psychological capital and radical innovation performance，while the acquisition of cognitive tacit knowledge has no mediating effect. The findings provide implications for knowledge management research. It also provides practical suggestions for enterprises to develop psychological capital and achieve radical innovation.