A uniform colour space (UCS) would be very useful for image applications such as gamut mapping, image compression, and evaluation of colour management and colour reproduction systems. Current colour spaces, however, can only be applied under a fixed set of viewing conditions. It is essential to construct a uniform colour space, which can predict colour difference under a wide range of viewing conditions. This paper describes a new uniform colour space J 'a 'b 'actually based upon one of the revised colour appearance models, CAM97s2 to fit the available small colour difference datasets including BFD-P, RIT-DuPont , Leeds and Witt . Our results show that J 'a 'b ' fits the above experimental datasets better than the current CIELAB and DIN99 spaces.