Rare metal deplating solution and preparation method thereof

The invention provides an environment-friendly and safe rare metal deplating solution and a preparation method thereof. A rare metal deplating solution comprises, by mass, 1%-2.5% of a metal corrosion inhibitor, 15%-25% of an organic solvent, 1%-10% of a penetrating agent, 5%-10% of a complexing agent, 0.3%-2% of a surfactant, 10%-40% of an etching agent and pure water, the metal corrosion inhibitor is m-diazacyclopropene, and the PH of the rare metal deplating solution is 7-9. The rare metal deplating solution is a weakly alkaline deplating solution, has the characteristics of easiness in obtaining, high efficiency, environment friendliness and low toxicity, is free of addition of strong acid, greatly guarantees the safety, protects a deplating container from being corroded, and is most suitable for titanium compounds and tantalum compounds; the method is applied to a titanizing die, the surface titanium film can be completely deplated through detection of an energy disperse spectroscopy, and the repeated ut