Abstract: To deal with the increasingly serious safety situation of civil air transportation, Montreal Protocol, 2014 amending Tokyo Convention, 1963 was passed in 2014, which redefined the power of aircraft commander and legal status of in-flight security officer. Through the analysis of Tokyo Convention, 1963 and Montreal Protocol, 2014, the paper holds that the responsibilities of aircraft commander and in-flight security officer are different, though their relationship involves both mutual cooperation and relative independence. Even though China has certain legal provisions on the power of aircraft commander, legal status of in-flight security officer and air marshal, their legal hierarchy is relatively low and there exists also an issue of power conflict. Therefore, it is necessary to improve the relevant legislations in China to better guarantee the safety of civil aviation transportation.