Immersive Virtual Reality (IVR) aims to bring simulated learning experience but could bring about higher cognitive load and be less accommodating to different cognitive styles. Meanwhile, Peer Instruction (PI), when integrated into IVR-based course, has the potential to address the needs of different cognitive styles and reduce cognitive load. This study, adopting a quasi-experimental research method, intends to explore the effects of PI in IVR-based course on learners, especially with two cognitive styles, namely Field-Independent (FI) and Field-Dependent (FD). A total of 65 junior high school students from two classes were randomly assigned to either experimental group or control group based on intact class. The research results indicate the positive effect of PI on learning by reducing cognitive load (d = 0.87), increasing motivation (d = 0.75), retention (d = 0.60) and transfer (d = 0.57) in IVR-based course. More specially, FD learners could benefit academically more from the PI than FI learners (d = 1.17). Therefore, we recommend peer interaction to be stressed in IVR-based course, with an attention to individual cognitive styles, to facilitate and enhance IVR resources designs and promote virtual experimental learning.