The work aims to propose a design model of APP interface design integrating emotional design and A-Kano model to scientifically obtain the weight of users' emotional needs and effectively improve the user experience satisfaction of APP interface, so as to solve the lack of emotional design in slimming diet APPs. Firstly, based on Donald Norman three level theory of product emotional experience, the elements of emotional design requirements were explored. Secondly, the A-Kano model was used to quantitatively evaluate the hierarchical attributes of each user need, and the importance ranking of user need was obtained. With a slimming diet APP as an example, it was demonstrated that the interface design model combining emotional design and A-Kano model could clearly present the attribute classification of users' emotional design needs, accurately sort the priority of needs, and standardize the subsequent interface design process. This shows that the emotional interface design guided by this method is feasible. It can effectively improve user experience satisfaction, and provide a new path for interface research and development.