The work aims to solve the problem on operation efficiency of multi-person collaborative design in complex mechanical design of fixed strip box automatic filling equipment. The task planning method based on fuzzy design structure matrix (FDSM) was adopted for task planning. The overall design task was decomposed according to the mechanical correlation scale. The coupling relationship between design task was quantified, and the fuzzy design structure matrix was constructed. The fuzzy design structure matrix was transformed into rows and columns, and the partition algorithm was used to decouple. Then the planned collaborative design task sequence and allocation were obtained. The validity of the planning results was verified by g-value, which showed that the compactness of the matrix before and after optimization has been reduced by about 24.95%, effectively reducing the mutual restriction of multi-person collaboration. It is concluded that the task planning method based on fuzzy design structure matrix (FDSM) can effectively improve the work efficiency of multi-person collaborative design of fixed strip box automatic filling equipment.