Abstract: From industrial design, an approach of graphic thinking is proposed to study users’ and designers’ patterns of tacit knowledge in product design. The concepts and attributes of graphic thinking are introduced and explored. Taken the sporting mobile phone form design as an example, protocol analysis is adopted with graphic thinking in three experiments to analyze users’ and designers’ tacit knowledge presentation processes from abstract level to concrete level. Based on data offered by the experiments, two types and patterns of tacit knowledge in the scheme design about form are proposed, and the relation with design requirements and design results is dis-cussed. The findings show that：① There is a distinct differ-ence between users’ patterns and designers’ patterns of tacit knowledge. ② Users are apt to presentation by image, design-ers are apt to both image and abstract. ③ Users’ tacit knowl-edge representation is intermittent, but designers’ is continuous and reticular.

Key words: Graphic thinking, Product design, Protocol analysis, Sketch, Tacit knowledge