As a core element of graphic design, color plays a decisive role in visual communication effectiveness. This paper systematically explores the impact mechanisms and enhancement strategies of color design on visual communication effects in graphic design. The study first analyzes the fundamental functions and principles of color in information delivery, visual guidance, and abstract conceptual expression. It then delves into how color design exerts core influences on visual communication effects through four key pathways: enhancing visual appeal, optimizing information delivery efficiency, evoking audience emotional resonance, and shaping brand perception. Building on this foundation, the paper proposes color design optimization strategies guided by target audience, information hierarchy, brand tone, and innovative technologies, aiming to provide theoretical references and practical guidance for design practice.