Function combination designs integrate multiple product functions into a single product carrier. In this article, we proposed a function combination design method based on the functional redundancy analysis of parent products for the conceptual design process. According to the design task, we analyzed each parent product function carrier, established an expression model of functional elements based on the functional basis approach, and constructed a functional structure of the parent product based on relationships among energy, material, and signal flow. Then, we established a product function redundancy matrix and carrier redundancy matrix, and obtained redundancy functions and the principle structure carrier. We constructed a function carrier matrix for function combination products, sought the appropriate principle, established a design structure matrix, analyzed the coupling relationship between the principle scheme and structure carrier, and obtained a conceptual scheme of combination products through operations including reuse, variant, removal, and increase. Moreover, we used a sticker removal machine as an example to verify the validity of our function combination method.