The work aims to solve problems of high differentiation of market needs and limited R&D investment in the R&D of gas safety detectors. Firstly, the Kano model was employed to conduct surveys on needs of R&D personnel and users to determine design needs. Then, based on the modular design concept, the corresponding relationship between function and shape was established, and the development strategy of "basic unit + shell shape" was proposed. Finally, a large number of modeling solutions were generated using shape grammar in conjunction with materials and processes. The final scheme was finalized. The innovative design method integrating Kano model, modular design and shape grammar was constructed to accurately obtain the R&D requirements and complete the innovative design of gas safety detectors. The innovative design method effectively solves the problems in the development of gas safety detectors and provides diversified design ideas for safety equipment products.