As the core content of secondary vocational art courses, color expression techniques have a deep connection with the cultivation of students' design thinking. Systematic learning of techniques such as color contrast and composition effectively stimulates students' divergent thinking and creativity, while training in color emotional expression fosters their unique aesthetic judgment and design perspectives. Based on the author's teaching practice at Wenzhou Overseas Chinese Vocational Secondary Professional School, this paper explores the influence mechanism of color expression techniques on students' design thinking and proposes corresponding teaching optimization strategies. Research shows that secondary vocational art education should construct a project-driven color teaching model and strengthen interdisciplinary integration practices to realize the organic unity of color technique training and design thinking cultivation.