A packet delivering method for a packet delivering apparatus includes: recording respective priorities of multiple packet delivering rules, which includes multiple first packet delivering rules and multiple second packet delivering rules respectively stored in a software layer and a main storage space of a hardware layer of the packet delivering apparatus; selecting a designated packet delivering rule from the first packet delivering rules; determining whether the main storage space is full; searching for at least one candidate delivering rule that meets a replacement condition from the second packet delivering rules according to the priorities of the designated data of the designated packet delivering rule and the second packet delivering rules when the main storage space is full; and replacing one of the at least one candidate packet delivering rule by the designated packet delivering rule when the at least one candidate packet delivering rule exists.