Timetable construction of mass rapid transit systems refers to the process of creating a time table within the existing constraints - such as the rail facilities, station locations, the control system, and the fleet sizesfaced by the operating organization in order to meet the transportation demand and safety requirement. MRTS’ safety and transportation efficiency, is directly impacted by the optimality of a timetable. Therefore, to the operating organization, the ability to quickly develop an optimal timetable becomes a tool to increase the system s efficiency. The purpose of this research is to integrate mathematical programs and computer technology to develop the decision support system(DSS) . In addition to developing the most effective timetable, the system can also show the number of different cars, stations and peak/off peak hour adjustment. This system can increase operation safety and the reliability of the timetable. This study use the Tamshui Line in Taipei for implementation of the DSS. Results show that it takes only 210 seconds to develop an optimal timetable. Also, results show : hat the ratio, the magnitude of adustment, and the stability of time-distance are better than past studies.