(1) An effective and precise pattern matching algorithm is important to intrusion detection system.

(2) For the problem of Chinese string matching, an improved multiple pattern matching algorithm is provided.

(3) The performance efficiency of a network intrusion detection system ( NIDS ) is dominated by pattern matching algorithm.

(4) It is composed of three parts: machine description, machine description processor and pattern matching algorithm.

(5) For the problem of Chinese string matching, a fast multiple pattern matching algorithm was provided.

(6) In order to enhance the ability of the synonyms recognition, this paper presents pattern matching algorithm based on the patterns of dictionary definition.