Apparatus and methods for performing a rule matching are disclosed. In one embodiment, an apparatus for performing a rule matching includes a content matching module and a first rule matching module. The content matching module searches the data stream for contents. The contents are organized into rules including a simple rule with a single content and a complex rule with multiple contents. The first rules matching module is coupled to the content matching module for determining whether the rules are matched by the data stream according to a searching result of the content matching module. To this end, the first rule matching module updates status registers according to the searching result and each status register can indicate whether one of the rules is matched by the data stream.