Monet's Water Lilies series is a benchmark of Impressionist color expression, spanning nearly three decades and presenting a continuous evolution of color structure and visual language. This paper takes image processing as the point of departure to extract the dominant hues, luminance distribution, and warm–cool contrasts of Water Lilies paintings from different stages, thereby revealing their underlying visual construction patterns and emotional trajectories. By quantifying image features, it builds a logical link between artistic style and digital models, and further explores the potential applications of color data in art education, digital creation, and the analysis of East Asian painting. The study aims to offer a practical paradigm for the integration of art interpretation and image processing technology.