The invention relates to a preparation method for lithium metal. The production method for high-purity lithium metal comprises two steps of synthetic reaction and reducing reaction, the synthetic reaction comprises the steps that raw material lithium carbonate and kalk or aluminium hydroxide are mixed, then are put into a reaction vessel to be calcinated at the temperature of 650 to 850 DEG C, after carbon dioxide and moisture are removed, intermediate products are prepared and are sieved and set aside; the reducing reaction comprises the steps that duriron or aluminium powder are added into the intermediate products prepared during the synthetic reaction to be as reducing agent, after being mixed, the intermediate products are pressed into spherical or cylindrical, then reducing reaction is performed under the vacuum and high-temperature condition, and the lithium metal is prepared. The production method has the advantages that the flow of the synthetic reaction is simplified, the production efficiency is effectively improved, the product purity is greatly enhanced, no waste material is generated, the side product is lithium-containing compound, which can be directly applied to the electrolytic aluminum industry, and all the required raw materials can be solved internally.