Usability is crucial to determine the success/failure of the user interfaces. This can explain the ever-increasing number of publications addressing the problem of usability integration during the development process. These studies aim to guide the development process of the user interface according to a set of usability attributes. In fact, the selection of the alternative transformation depends on the usability attributes that will be met. However, the major weakness of these studies is related to the choice of the optimal alternative model transformation. The present paper introduces an approach that addresses this weakness and generates the user interface conceptual model with an optimal usability. The main objective is to select from all the possible alternative transformations the optimal one which maximizes the usability value in a specific context (e.g., small-screen device, novice user). By considering the inherent features of the model-driven engineering, the proposed approach aims to generate the final user interface with an optimal usability value.