Abstract: Air marshal and in-flight security staff have been deployed on Chinese civil aviation aircraft as a full-time security force for a long time. In recent years, the relevant law was constantly revised and improved, and occupational identity, legal status, qualification, responsibility and authority of the air marshal and in-flight security staff were all confirmed and normed. But in the practice of Chinese international airline business, there are some embarrassing dilemmas in abroad such as the routine duties of the air marshal and in-flight security staff and their disposition of cases. To find the key to the problems, the paper makes a comparative study on international law and domestic law in the aspects of legislation, standard and proposal. The research finds that there are differences on conception, status, responsibility and authority between the international law and the domestic law on the full-time security force. At last, combined with China's national conditions and reality, the paper puts forward improvement plans for both the responsibility and authority permission setting and international co-operation.