Abstract: The AC-BM algorithm has the advantages that multiple pattern strings are searched simultaneously and that number of characters of moving text string is optimized．But,they are searched only in one text string in one time．To search in multiple text strings simultaneously,this paper designed multi-objective AC-BM algorithm．By union operation of two automatons,multi-objective multi-pattern tree automata was structured,and by BM algorithm’s bad character move technique,function of moving a set of text strings was designed．In the Snort,2-goal AC-BM algorithm and 3-goal AC-BM algorithm were implemented．On the condition that if in multiple text strings a pattern string is found,the algorithm stops,the result shows the new algorithm is obviously superior to AC-BM algorithm in time.

Key words: AC-BM algorithm,Pattern string,Pattern matching search,Automata,Bad character move technique,Snort