Abstract: With the development of digital economy, platform enterprises have sprung up as a major force driving social development. Under network effects, the platform economy has quickly formed a winner-takes-all landscape in a short period of time, with many business areas dominated by a few early-established, powerful platforms. To expand market power, these platform enterprises have pursued killer acquisitions—targeting start-ups, motivated by stifling potential competitors, and employing data monopoly as the instrument. Due to the institutional defects, the antitrust regulation faces numerous practical difficulties in dealing with killer acquisitions by platform enterprises, such as declaration thresholds and substantive examination. In this regard, existing regulatory tools should be refined by the application basis and specific rules of the concentration of undertakings system ; for new regulatory tools, the EU "gatekeeper" system provides a viable regulatory path.