Connect6 is a kind of k-in-a-row game that was introduced by Professor I-Chen Wu. It is a fair and complex game with simple rules. This study is based on a Connect6 program Ant developed by Yu-Chen Lai. We improve its pattern classification, evaluation method, and threat-space search algorithm to promote its win rate significantly. Experimental results show these ideas really make Ant become much stronger. After modification, Ant obtained the silver medal in TAAI 2010 computer game tournaments and the bronze medal in TCGA 2011 computer game tournaments.