Power disparity, as an important form of internal team hierarchy, presents a "double-edged sword effect". To reconcile the inconsistent effects and systematically explore the different mechanisms of power disparity, this study constructs a comprehensive theoretical model based on power functionalism and power conflict theory, with team coordination and team conflict as dual mediators, and power legitimacy as moderator. By collecting valid questionnaires from 76 teams across 27 different types of companies in various regions, statistical analysis and hypothesis testing were conducted on the data. The results conclude that power disparity positively influences team innovation performance through the team coordination path and negatively affects it through the team conflict path. However, under the moderating effect of power legitimacy, the negative effect of the team conflict path is suppressed, and the positive effect of the team coordination path is strengthened, thus ensuring that power disparity has a positive effect on team innovation performance. This study provides a useful reference for designing the power hierarchy within enterprises, and offers profound insights into effective organizational structure and decision-making processes.