Abstract: Related to passengers' rights and interests, the priority boarding rule may be used directly to deny boarding to passengers when a flight is oversold. Not adjusted by special laws, this rule is made by airlines themselves, and thus, there are some problems such as improper notice and unfair content. In practice, priority boarding rules are roughly divided into "first come, first served" and "comprehensive measurement" rules. The application of priority boarding rules in flight overbooking and rejection should draw lessons from foreign experience to bridge the basic theoretical gaps at the legal level, and specify its specific contents and notification obligations in the regulations.