The work aims to explore an innovative design path of braille writing modifiers to solve the problem of high error rate in braille writing. Firstly, the user demands of blind students for braille writing modifiers were learnt through user interview. Then, the relationship matrix between user demands and technical targets was constructed according to the QFD theory to obtain the priority of technical targets and determine key technical targets for design of braille writing modifiers. Once again, the FBS was adopted to transform the key technical targets into functions and obtain the structural information of braille writing modifiers by FBS mapping. F12 (keys), F21 (braille structure) and F32 (fixed structure) showed up to be the most important. The top 6 technical targets were corresponded to the four functions of interaction, braille, modification and replacement and then taken as the functional starting point to achieve the transformation from function to behavior, and from behavior to structure mapping to guide the design of braille writing modifiers. The study verifies the feasibility of QFD and FBS model in design of braille writing assistive tools, which provides a new idea for improving the efficiency of braille writing for blind students from the perspective of innovative design.