Macroscopic superlubricity has drawn attention for its potential to reduce friction and wear in engineering. In this study, a composite lubricant was developed by combining yam polysaccharide with polyethylene glycol. Superlubricity was achieved under 516.4   MPa pressure between 440   C stainless steel and SiC ceramic, with an average friction coefficient of 0.0051. Notably, the stainless steel showed a low wear rate of 1.291×10⁻⁸ mm³·N⁻¹·m⁻¹ after six hours and maintained performance even after 30 days of rest. This effect is attributed to the rigid structure of the polysaccharide backbone, which limits excessive hydrogen bonding and promotes the formation of a gradient film composed of inorganic, mixed, and organic layers during friction. These findings provide new insights into developing eco-friendly, water-based superlubrication systems.