In this book, writers believed, by using various colors in urban space could be improved legibility in our cities. Also, colors have other effects in urban space such as vitality, permeability, affiliation, variety and etc. the purpose of writing this book is, study effects of colors on urban space and legibility. Therefore this book has been organized in 4 chapters. In first chapter has been discussed about colors, in this section has been discus about history of colors and different meaning of colors in various culture and colors psychology. In Second chapter has been studied about some urban concept such as: legibility, vitality, and the effects of colors on them, also was discussed the role of colors on urban design. In third chapter was studied world experience about function of colors in urban design and was introduced 13 most colorful cities in world. Then in final chapter was analyzed the role of colors in order to improving urban Legibility by using case study in Asian cities such as Iran country.