Abstract: Currently, there exists a notable divergence in the developing trend of rules on outer space arms control. Some nations put forward the notion of “space threat” in an effort to promote the program of “Reducing Space Threats Through Norms, Rules and Principles of Responsible Behaviors”. Deterrence and threat are closely related, as there can be no deterrence without threat. Contemporary international law recognizes the legitimacy of limited deterrence, which means that it also acknowledges the legitimacy of some threats. The term “threat” in the Chart of the United Nations primarily refers to “threat of force”. If this definition applies to the context of outer space, it becomes necessary to analyze all potential elements of space threats, including the subjectivity (intention), the actor (whether it can be attributed to a state), the act (measurable, attributable and demonstrable), the resulting damages, and the causation, etc.. In other words, a certain threshold needs to be met---there must be a high probability of resorting to force. The so-called “space threats” cited by some States are selective and targeted in nature, with the deficiencies of incomplete coverage and reliance on subjective judgment. When interpreted within the framework of existing international law, these so-called “space threats” cannot be recognized as internationally wrongful acts. Contemporary international rules on outer space arms control are the result of compromises reached by major powers under their deterrence strategies. Neglecting this historical trend and promoting rules that favor certain States’ military dominance in outer space would undoubtedly undermine strategic stability and equilibrium, and ultimately severely impede the collective efforts of the international community to prevent an arms race in outer space.