The work aims to combine the fuzzy Kano model and the extension innovation method to solve the problems of serious homogeneity and low user satisfaction of special carrying tank cars. An innovative design method based on the combination of the fuzzy Kano model and the extension innovation method was proposed. First of all, the extension analysis was carried out on the special carrying tank cars. A matter-element model was established. The expansion analysis was carried out and the fuzzy Kano model was used to output the importance of the quality elements and extract the key design elements. Secondly, combined with the data analysis results of the user's needs, the matter-element mathematical representation model of the special carrying tank cars was transformed by the extension transformation method, and a new product creative model was obtained. Finally, the optimal solution was obtained through the goodness evaluation method. Through the optimized design of the special carrying tank cars, the appearance, safety performance and functional characteristics were improved. It is proved that the design method combining the integrated fuzzy Kano model and the extension innovation method can improve the user satisfaction and market competitiveness of the special tanker.