Abstract: Exploring the stability of continuous basalt fibers in various media environments is crucial for expanding their application in composite insulation materials. We compared the aging characteristics of ten groups of continuous basalt fibers from different origins with E-glass fibers in acidic, alkaline, salt-rich, and high-temperature salt-rich environments. The aging mechanism of continuous basalt fibers was analyzed, and the key components that contribute to the weathering resistance of basalt fibers were identified through grey correlation analysis. The results indicate that over 50% of basalt fiber samples have better salt alkali resistance than E-glass fibers. In alkaline environments, the reactivity of Si, Al, and B elements with OH^- may cause two types of fiber damage. Among them, basalt fiber has a relatively low degree of damage due to the high content of Ca and Mg forming the hydroxide attached to the fiber surface. Under salt-rich environments, elements such as Ca, Na, K on the surface of fibers escape into the solution, resulting in a loose surface structure of the fibers and the formation of defects under the action of medium infiltration and swelling, thus the strength of the two types of fibers will synchronously decrease. However, basalt fibers still exhibit higher mechanical characteristics. In summary, basalt fibers are more suitable for application in medium and low-voltage composite insulation products or electrical materials with high mechanical requirements in saline alkali-polluted areas.