Our starting point is colour and the notion that colour makes a difference. We studied colour science and colour geography in order to research the architecture facades in Karlskrona. The first part of the paper introduces the significance of our study, background, research objective and methodology, along with the definitions of some concepts，and urban colourscape situation of foreign counties and China. The second part of the paper expounds problems of urban colourscape and discusses principles, significance and function of urban colourscape planning. The third part of the paper analyses the colourscape planning of Copenhagen in order to demonstrate the significance and process of colourscape planning. It also investigates geography, history and culture of Karlskrona. The fourth part of the paper has the results of our research- a colour program of Karlskrona's architecture. The fifth part of the paper summarize the whole thesis.