The importance of competitive advantage for platform enterprises' long-term development necessitates explorations of the factors that influence such an advantage. This study empirically investigates the impact of tax compliance on the competitive advantage of platform enterprises, specifically focusing on the efficiency of contract enforcement using online sales data from the WIND database. The findings reveal that platform enterprises' adherence to enterprises' tax compliance enhances the competitive advantage effect. The results of the panel threshold model regression demonstrate that the positive contribution of tax compliance to competitive advantage is contingent on contract enforcement efficiency. Moreover, the promotional effect is more pronounced in regions with superior contract enforcement efficiency, indicating a nonlinear marginal incremental effect. Heterogeneity analysis reveals that the influence of platform firms' tax compliance on competitive advantage effects is constrained by factors such as tax administration strength, information transparency, firm size, and regional variations. These findings deepen our understanding of the relationship between tax compliance and platform enterprises' competitive advantage, offering valuable insights for such enterprises’ decision-making concerning competitive strategies.