Abstract: With the development of digital economy, platform enterprises have sprung up and become an important force to promote social development. Under the action of network effect, the platform economy has formed a winner-takes-all situation in a short period of time. Many business areas are controlled by a small number of platform enterprises established earlier with strong strength. To expand their market power, these platform companies have dominated killer acquisitions, which takes start-ups as potential targets, stifling potential competitors as the motivation, and data monopoly as the means. Due to the defects of the system, the antitrust regulation has many practical difficulties in dealing with the issue of killer acquisitions by platform enterprises, such as declaration standards and substantive examination. In this regard, on the path of existing regulatory tools, the application basis and specific rules of the concentration of undertakings system should be adjusted; on the path of new regulatory tools, the EU “gatekeeper” system provides a reasonable regulatory path.