The work aims to propose a design method based on a theory of empathetic psychological processing mode, to solve the problem that it is difficult to make users have strong empathic cognition on the current designs of red cultural products, which makes poor design effect on affective experience. A comparative study of several models of cognitive empathy mechanism was done in the paper. According to the facts of users' perception and processing of the current designs of red cultural products, Vignemont's "Late Appraisal Model" was chosen as the psychological theoretical basis to develop an empathic design method used in red cultural products, and the detailed design operations and thinking process of the method were described through a practical design case. According to the guidance of the empathic design method, an undergraduate from Fuzhou University completed the design work in the graduation project. The design theme of the work was a treadmill offering the Long March scenario experience. The main design goal was to make users have empathy with the long march soldiers in an immersive experience. The design work received the evaluation opinions from the judges of final project defense, and the design effect was verified. The conclusion of the study shows that the empathic design method based on the "Late Appraisal Model" has good operability and rationality, and the design output guided by this method can achieve the design goal of making users have empathic cognition of red culture.