This study aims to solve the problem of the lack of functional analysis and systematic design thinking in the design of some existing automobile front faces, with the goal of reducing the loss of design time and shortening the design cycle. Firstly, each functional element of the automobile front face is extracted by inductive method and functional relationship is established to analyze the functionality of the automobile front face emphatically. Secondly, the evaluation index system of automobile front face is established by using hierarchical analysis method, and the scores of automobile front face at all levels are combined with consumer research and experts' opinions, and the comprehensive weights are determined in order to judge the importance of functionality in the design of automobile front face at all levels. It is found that the comprehensive weights obtained by using hierarchical analysis method, A, B grade automobile front face should consider more about functionality when designing, while C grade automobile front face needs to take into account the balance of functionality, experience and appearance, and D grade automobile front face needs to pay more attention to the appearance when designing; the comprehensive weights obtained by evaluating the results of consumers and professionals have improved the accuracy and objectivity of the data. Finally, the triangular fuzzy number is used to optimize the functionality of the morphological scheme, and the best functional principle scheme is selected. The triangular fuzzy number on the functional scheme preference quantifies the fuzzy indexes, and can judge the degree of its importance between the indexes. It is an important research to integrate the functionality evaluation into the automobile front face design, which provides a reference for the automobile front face design.