A routing apparatus and a method thereof for processing a network packet are provided. In the present method, a plurality of packet processing rules comprising a plurality of conditions are defined in the routing apparatus, and a relationship between each condition and the relative packet processing rules is recorded. After a packet enters the routing apparatus, it is determines that whether a specific packet processing rule can be found among the packet processing rules according to a plurality of packet information and the predefined relationship. If the specific packet processing rule can be found, the packet is processed by the specific packet processing rule. As a result, the performance of the routing apparatus and the processing speed can be increased.