Taking Changchun's three major historical and cultural districts as the research subjects, this study conducted a survey on the current status and color measurement of buildings with iconic characteristics within these areas. It summarized the existing color layout patterns, revealing that historical and cultural buildings exhibit relatively uniform color schemes compared to residential structures, while commercial buildings, leisure and entertainment facilities, and cultural venues feature more diverse color palettes. Guided by the planning principles of “regional unity” and “individual character,” this study proposes a color palette and planning recommendations. These solutions effectively express regional cultural identity and preserve architectural heritage while establishing a unified online and offline urban image perception model for future city branding initiatives.