With the rapid advancement of high-voltage direct current ( HVDC) transmission and power electronics technology, the long-term stability of electrical properties in insulating materials has emerged as critical factor for ensuring grid safety. Cross-linked polyethylene ( XLPE) and polypropylene ( PP), leveraging their unique performance advantages, are widely used in high-voltage cables and power capacitors, respectively. However, these materials undergo aging under combined effects of electric fields, heat, oxygen, moisture, and other factors, leading to electrical performance degradation. Antioxidants, by inhibiting oxidative side reactions, not only delay material aging but also significantly influence space charge distribution and conductivity of polyolefins, thereby serving as a key tool for regulating electrical properties. This review focused on two kinds of high-demand polyolefins, XLPE and PP, and systematically summarized the impact of antioxidant types on their electrical performance as well as the mechanisms linking antioxidants to electrical properties via crystallization regulation, and proposed future research directions: functional molecular design of antioxidants ( emphasizing interface stabilization) and targeted degradation of antioxidant residues. These advancements aim to address current challenges and guide the development of next-generation high-performance insulating materials.