The work aims to take the shoulder and elbow exoskeleton rehabilitation robot as a research example to analyze the correlation between the user's emotional needs and the functional form of the product according to the Bayesian network in combination with the theory of perceptual engineering to excavate the characteristics of the product form under the specific emotion. Users' perceptual evaluations related to shoulder and elbow exoskeleton rehabilitation robots were collected, and emotional feature words of users and functional feature words of products were extracted; A Bayesian network-based derivation model of the relationship between users' emotional needs and product functional form was constructed, and the changes in the relationship between users' emotions and product functional form features under specific data were analyzed; According to the users' emotional feature words and product form feature samples collected, a product form imagery model was constructed by performing perceptual evaluations of the product features sample so as to converge the specific product appearance features; Finally, the product design was put into practice to verify the feasibility of the design scheme. A Bayesian network-based model for the derivation of the relationship between users' emotional needs, product functional form and evaluation of product form imagery was constructed, the correlation path between users' perceptual needs and product appearance and functional structure was formed, and the design strategy for product form features that satisfied users' emotional needs was elaborated. Using Bayesian network to explore the correlation between user's emotion and product's functional form, and constructing product form imagery model can more accurately excavate the product form characteristics corresponding to user's specific emotion, provide design direction and logical basis for designers to carry out product emotional design, reduce the uncertainty of the design decision-making, and realize the innovation of the product form design based on user's experience needs as the starting point.