This study addresses the issue of monopolies in the Internet platform economy by analyzing their causes and evaluating effective antitrust measures to maintain market fairness and encourage economic prosperity. Focusing on monopoly dynamics, including the network effect, capital influence, and market dominance, we apply evolutionary game theory and empirical analyses to devise a game theoretical model. This model helps simulate monopoly evolution and the potency of antitrust strategies. Our findings illustrate a direct correlation between monopoly growth and factors such as user base size, capital consolidation, and market control, with platforms frequently adopting monopolistic tactics for revenue maximization. Following antitrust regulatory actions, industry concentration shows a notable decrease, with metrics of total assets and net sales concentration dropping by 0.059 and 0.069, respectively. The study outlines critical regulatory strategies for enhancing market regulation, competition facilitation, and encouraging innovation. Effective antitrust enforcement is vital for optimizing market structures, spurring industry innovation, ensuring consumer welfare, and supporting the healthy progression of the Internet platform economy.