Based on the theory of group decision-making power allocation, using the data of A-share non-financial listed companies and their subsidiaries from 2007 to 2021, this paper examines the relationship between the personnel control and enterprise technological innovation on agency costs and knowledge transfer costs. The empirical result shows that there is an inverted U-shaped relationship between personnel control and enterprise innovation. Specifically, with the higher degree of personnel control, the overall innovation level of the business group is improved, but it gradually decreases after the turning point. The mechanism discussion shows that personnel control reduces agency costs, but increases the knowledge transfer costs between headquarters and subsidiaries. The heterogeneity test reveals the relationship is weakened in the groups with large scale subsidiary and better internal information environment as well as state-owned enterprise groups. To enhance technological innovation level, group managers should establish appropriate power allocation rationally and optimize personnel control.