Abstract: With the rapid development of low-Earth-orbit (LEO) mega constellations, the increasing density of space objects in orbit has aggravated the orbital congestion and posed potential threats to the security of outer space operations. In the absence of specific space traffic regulations, the massive generation of space debris has raised the probability of satellite collisions and led to frequent close-proximity reconnaissance activities. However, there is a lack of legally binding, enforceable norms capable of regulating state behavior, and the trend toward soft law in outer space governance has made a host of rules unable to acquire mandatory force. Against this backdrop, this study traces the origin of the obligation concerning harmful interference under Article 9 of the Outer Space Treaty, clarifies the effectiveness and implementation standards of the consultation obligation in regulating physical interference in outer space, and proposes more practical measures under the principles of international cooperation and obligation of due regard. The mechanism concerning harmful interference puts forward three specific constituent elements: a planned activity or experiment in outer space, a peaceful purpose, and a reasonable belief in the existence of potential harmful interference. These elements serve as the basis for determining whether harmful interference exists and fulfill its obligation to negotiate harmful interference promptly. By constituting explicit consultation standards and procedures, it is imperative to ensure the specific implementation of the harmful interference, activate the harmful interference clause, and provide clearer legal guidance for the governance of LEO mega constellations.