The invention discloses a hub bearing lubricating grease and a preparation method thereof. In the lubricating grease, composite lithium soap is taken as a thickening agent, an antirusting agent, an antioxidant, an extreme-pressure anti-wear agent and a waterproofing agent are added, and a nanometer additive and the like are added according to different proportions. The lubricating grease is prepared by the processes including saponifying, dehydrating, blending, shearing, homogenizing, grinding, filtering, degassing and the like. A lubricating grease composition has the advantages of high dropping point, high wear resistance, high extreme pressure resistance, high high-low temperature performance and the like, has high water resistance and rust resistance, and is suitable for lubricating the automobile bush bearings under harsh working conditions.