Disclosed is a safe anti-leakage case of a lithium ion battery. The safe anti-leakage case of the lithium ion battery comprises a case body for placing the battery, and a sealing cover plate. The upper end of the case body is open, the back surface of the sealing cover plate is provided with a downwards convex sealing boss, the opening of the upper end of the case body is provided with concave steps corresponding to the sealing boss; after the sealing cover plate covers the opening at the upper end of the case body, gaps can be formed between the sealing boss and the convex steps, then the connecting surfaces of the sealing cover plate and the case body are sealed through welding, the upper portion of the opening at the upper end of the case body and the lower portion of the edge of the sealing cover plate can form molten residues due to heating, which can be filled between the gaps between the sealing boss and the convex steps and form a sealing state after cooling down. The safe anti-leakage case of the lithium ion battery is high in safety and can achieve good anti-leakage effects.