Mahjong is an imperfect information game which requires skills, strategies and calculation to be a good player. In this research, we developed a computer Mahjong program, called “TimeoutKing,” based on the rules of Taiwanese Mahjong game. The program can find highly-winning tile patterns by using some heuristic rules to analyze its own tiles. Though continuous trials and improvements, the program gradually increases its wining rate. By combining these heuristic rules with the game tree search algorithm, “TimeoutKing” won the third prize in Mahjong group in 2016 TAAI Computer Game Tournament.