As the core entrance to human-computer interaction, the design of the display system has a crucial impact on the user's immersive experience. This paper focuses on the influence of field of view size on immersion in the virtual reality display system, and constructs six virtual scenes with different field of view sizes based on virtual reality near-eye display technology. The subjects complete the perceptual interaction task in the scene, and the EEG device is used to record their EEG activity data in real time during the experiment to quantify the objective immersion. At the same time, the test subjects reporte their subjective immersion status through the immersion questionnaire after each task is completed. The experimental results show that the field of view has a very significant effect on the quantification results of subjective and objective immersion (p<0.001). Within the diagonal field of view (from 60° to 110°) of the experimental design, the larger the field of view, the greater the immersion. Based on the influence mechanism of field of view size on immersion, this paper constructs a model of the influence of field of view size on immersion, and the coefficient of determination of the model reaches 0.8488. The research content is expected to provide a reference for the design of immersive display systems for the metaverse and the optimization of user perception effects.