In order to improve the objectivity and operability of design thinking method, a perfect design thinking process model is constructed. Extenics and TRIZ are integrated to optimize the three important stages of problem analysis, solution and evaluation in the process of design thinking. The extension model is used to establish the formal problem definition model. The extenics and TRIZ tools are integrated to build the problem solving model, combining TRIZ ideality rule and extension superiority evaluation. And an ideal superiority evaluation method is proposed. The design thought process model, which can be combined with TRIZ, is constructed, and the rationality and feasibility of the model are verified by the design of the smart shopping cart.The design thinking process model based on the fusion of extenics and TRIZ is more objective and operable, which is of great significance to support the practice of product innovation design.