Against the social background of the gradual transformation of the social pension mode and the arrival of the ageing age, the tool design of fitness walkers for the elderly was studied. In this paper, the physiological and psychological status of the elderly with mild or moderate stroke or unable to exercise due to the decline of physical function was analysed. In addition, the corresponding elderly fitness walker product market research was studied. Aiming at these problems, this paper proposes a set of elderly fitness walker frames based on the ergonomic semiotic approach of the product architecture design (SAPAD) model. First, the development and structure of artificial engineering is introduced in detail. Then the framework of walking aid for the elderly based on the SAPAD model is proposed, and the SAPAS model and walking aid for the elderly are introduced, respectively, along with the framework of simulation design and application. The experimental results show that the framework of elderly fitness walker based on the ergonomic SAPAD model can be implemented. It can be applied to the elderly’s fitness assistance. A fitness walker can be suitable for the elderly who want to continue to exercise; it also hopes to care for the elderly who need to exercise from the perspective of the product.