In this paper, the aramid fiber surface was modified by plasma, and the effects of plasma on the interfacial properties of aramid fiber reinforced epoxy resin (AFRP) was studied. The shear strength between aramid fiber and epoxy resin is notably enhanced after undergoing plasma treatment. Additionally, the AC breakdown strength of the treated samples can reach up to 33.2 kV/mm, which is 13.7% higher compared to the untreated samples. After treatment, the conductivity and dielectric constant of the samples decreased to some extent within a certain range. When compared with untreated samples, this provides a method to enhance the interfacial properties of aramid fiber reinforced epoxy resin composites. This could be a valuable development for using such materials in HV (high voltage) electrical equipment.