Abstract: As a significant concept related to financers'security interests in space industry, space asset was for the first time introduced in the Cape Town Convention of 2001 and defined under the Space Protocol of 2012. By examining and analyzing closely this new concept, the paper clarifies the applicable rules related to space asset and aircraft object under the Aircraft Protocol of 2001, and compares the differences and similarities between space asset and space object under the UN Space Treaties. The paper holds the view that the approach adopted in defining space asset can circumvent the impasse of delimitation issue and broaden the scope of assets, which is practically advantageous. However, certain concurrence of applicable rules is possible between the Space Protocol and the Aircraft Protocol, which may cause legal uncertainties. Besides, the space asset is different from the space object in terms of legislation orientation, value and approach, but also there are similarities and overlapping areas. Study on the concept of space asset would contribute to the understanding of its influence and challenges for the current international space law.