The invention discloses a method for preparing beryllium chloride. The method includes adding beryllium particles and absolute ethyl ether into a reaction vessel with a condensation reflux device in inert atmosphere; filling the reaction vessel with dry hydrogen chloride gas and keeping reflux of ethyl ether in the reaction vessel at bubble speeds; allowing the beryllium particles to completely disappear to obtain transparent liquid with few solid impurities; filtering the transparent liquid in a glove box and cleaning solid by the aid of the absolute ethyl ether; concentrating filter liquid in the glove box and extracting the ethyl ether to obtain beryllium chloride solid; sufficiently stirring and washing the beryllium chloride solid by the aid of anhydrous benzene, filtering the beryllium chloride solid, cleaning the beryllium chloride solid by the aid of benzene and drying the beryllium chloride solid to obtain the high-purity beryllium chloride. The method has the advantages that the method is easy to implement and can be carried out at the room temperature, and chloride generated during reaction on metal impurities and hydrogen chloride is purified under different-solubility conditions of the chloride in the ethyl ether and the benzene; the ethyl ether and the benzene which are solvents for reaction are simple, are easily available, have low boiling points and are easy to remove, reaction conditions are simple, high temperatures and high pressures are omitted, and the method is only required to be carried out in the inert atmosphere.