The invention discloses a deposited metal stripping agent for stripping metals deposited on the inner surface of a chemical plating tank and a preparation method of the deposited metal stripping agent. The deposited metal stripping agent comprises the following components: 250-300ml/L sulfuric acid (98%), 80-100ml/L hydrogen peroxide, 50-60ml/L alcohol, 2-3g/L urea, 25-30g/L tartaric acid, 20-25ml/L propylene glycol, 0.01-0.02g/L sodium lauryl sulfate and the balance of water. The preparation method comprises: adding running water the volume of which is 1/2 of that of a prepared liquid into a container at normal temperature; slowly adding the sulfuric acid (98%) while stirring continuously; then sequentially adding hydrogen peroxide, alcohol, urea, tartaric acid, propylene glycol and sodium lauryl sulfate; continuously stirring to dissolve the added substances; adding the balance of running water; and stirring until the mixed solution is homogeneous and transparent. As nitric acid is not contained, the deposited metal stripping agent disclosed by the invention does not generate harmful gas, is environment-friendly and pollution-free; and meanwhile, the cost comparison of each component is relatively low, thus the cost is low.