David Hockney's Swimming Pool series is one of the important representatives of figurative painting in the late 20th century., using color block division composition to redefine the space and visual rhythm of the picture. This paper takes "Bigger Splash", "Portrait of an Artist (Pool and Two Portraits)" and "Sun Pool" as the research objects, and explores the specific use of color block segmentation in their creations. Firstly, the concept and method framework of color block segmentation composition are defined. Then, the color structure and psychological effects of the main color field, secondary color field and accent color in the pool series are analyzed. Finally, the schematic representation of water is discussed, and the metaphorical connotation of quadratic segmentation is explained. Research shows that Hockney transforms the everyday scene of the pool into a visual structure that is both decorative and spatial, skillfully blending realistic and abstract elements through rational and sensual color block choreography.