This study is aimed at seat design optimization for high-speed train based on the Malaysians sitting anthropometrydata focusing on seat fit parameters. An analysis of anthropometry data composed of 15 dimensions that arerequired in seat design was done with 50 male subjects. These data were collected through direct measuringmethods with standard equipment. According to the Malaysian automotive seat fit parameters, the backrest width,backrest height, cushion width, and cushion length were established based on these anthropometric dimensions:interscye breadth (5th percentile female and 95th percentile male), hip breadth (95th percentile female), sittingshoulder height (5th percentile female), and buttock-popliteal length (5th percentile female), respectively. Thisstudy uses the CATIA software to design and analyse the proposed seat design. The fit parameters proposed for thenew design are seat height, 380mm; cushion width, 450mm; backrest width, 450mm and backrest height, 850mm.The CATIA human activity analysis (based on Rapid Upper Limb Analysis, RULA) was also executed. From the study,the new conceptual seat design gives the most optimized fit when compared to the current seat.