Abstract: Any legal system contains breach of obligation under its responsibility system. To ensure one party can effectively obtain indemnity, the law established the system of damage compensation. The domestic civil law in China sets that if there are damage facts and the facts have causal relationship with the harmful consequences, there should be damage compensation liability. International law established the international responsibility which proposes that both international wrongful acts and international law non-forbidden actions should bear international liability for damage compensation by means of repristination or compensation. In outer space law, damage compensation can be found mainly in the principle norms of Outer Space Treaty and the specific provisions of Liability Convention. The present damage compensation system has problems such as scattered treaty provisions, vaguely-defined terminology, lack of legislation in private activity, unclear choices among treaties, etc. The completion of damage compensation mechanism of outer space should start with the unification of outer space treaties, revising regularly the outer space legislation. The definition of damage, launching states, space objects should be further clarified and privatization of outer space activity legislation should be increased to make the alternative application among treaties of damage compensation more clear.