The invention discloses an environment-friendly inorganic antioxidative lubricant for hot rolling of steel. The lubricant comprises the following raw materials by weight: 75 to 80% of water, 5 to 10% of potassium dihydrogen phosphate, 7 to 15% of polyphosphate and 0.1 to 0.5% of nanometer oxide powder. A preparation method for the lubricant comprises the following steps: dissolving potassium dihydrogen phosphate in water so as to obtain a primary solution; then subjecting polyphosphate to sintering, cooling and triturating at a certain temperature and dissolving triturated polyphosphate in the primary solution; and finally adding nanometer oxide powder and carrying out uniform mixing so as to obtain the inorganic antioxidative lubricant. The inorganic antioxidative lubricant has excellent lubrication performance and cooling performance, can effectively inhibit excess oxidation of the surfaces of a roller and steel and enables a rolled product to have a shiny surface and surface oxidation of the roller to be uniform. The inorganic antioxidative lubricant also has the excellent characteristics of easy solubility in water, easiness in removal, no pollution and the like.