This research aims to overcome these problems of existing poker cards, such as low efficiency, low hold-ability and limited shapes via combining ergonomics and user-centred method. Through the investigation and analysis of the existing playing cards, combined with the user experience and ergonomics, this research makes an improvement design by using the equal width curve characteristics and stability of Reuleaux triangle. Furthermore, the whole process of playing cards shall be studied first, a Reuleaux triangle shape was proposed. This shape was convenient for users to grasp and hold. The brand-new design is not only enriching the shape of traditional Poker cards, but also can improve the efficiency of card collection and grasping experience. Moreover, statistical analysis also shows that the design significantly creates greater the user experience.