Title: Name Your Colour For the Task: Artificially Discover Colour Naming via Colour Quantisation Transformer. Abstract: The long-standing theory that a colour-naming system evolves under the dual pressure of efficient communication and perceptual mechanism is supported by more and more linguistic studies including the analysis of  four decades’ diachronic data from the Nafaanra language.  This inspires us to explore whether artificial intelligence could evolve and discover a similar colour-naming system via optimising the communication efficiency represented by high-level recognition performance. Here, we propose a novel colour quantisation transformer, CQFormer, that quantises colour space while maintaining the accuracy of machine recognition on the quantised image. Given an RGB image, the annotation branch maps it into an index map before generating the quantised image with a colour palette, meanwhile the palette branch utilises a key-point detection way to find proper colours in palette among whole colour space. By interacting with colour annotation,  CQFormer is able to balance both the machine vision accuracy and colour perceptual structure such as distinct and stable colour distribution for discovered colour system. Very interestingly, we even observe the consistent evolution pattern between our artificial colour  system and basic colour terms across human languages. Besides, our colour quantisation method also offers an efficient quantisation method that effectively compresses the image storage while maintaining a high performance in high-level recognition tasks such as classification and detection. Extensive experiments demonstrate the superior performance of our method with extremely low bit-rate colours. We will release the source code upon acceptance. 