In order to optimize the emotional interaction between human and robot, the identifiability of single-mode emotion expression of humanoid robot action was studied, and the influencing factors of humanoid robot action emotion recognition were explored. Taking the humanoid robot NAO as an example, the recognition, potency and arousal degree of the emotion expressed by the NAO action of the robot are obtained by questionnaire survey based on the discrete emotion model. The emotion recognition, potency and arousal degree of the humanoid robot action are studied. Based on the cognitive matching theory, the emotional expression differences between humanoid robot action and human simulated action and human natural action are studied The influencing factors. It is found that human beings can recognize emotions in different emotional semantics through the single-mode emotion expression of humanoid robot action. The robot shape, the amplitude, speed and strength of action are the influencing factors of emotion recognition. The relationship model between humanoid robot action and emotion semantics, valence and arousal degree is established, and the emotion energy diagram of humanoid robot action is also established, which provides a more systematic reference model for robot emotion expression and action interaction design.