The invention relates to a method for etching germanium antimony tellurium alloy materials, which comprises the following steps: providing a germanium antimony tellurium alloy layer and arranging the germanium antimony tellurium alloy layer on the surface of a semiconductor substrate; covering the surface of the germanium antimony tellurium alloy layer with an etched barrier layer; patterning the etched barrier layer so as to expose the surface of the germanium antimony telluride alloy layer at a reserved part; and immersing the exposed surface of the germanium antimony telluride alloy layer in atmosphere of etching gas containing halogen and passivant. The etching gas containing the halogen is mixed with the passivant, the chemical formula of the passivant is CxHyF4x-y, wherein x and y are integers, the x is larger than 0, and the y is larger than or equal to 0 and smaller than 4x; the etching gas is excited into a plasma so as to etch the germanium antimony tellurium alloy layer. The invention has the advantages that the passivant with the chemical formula of CxHyF4x-y is added in the etching gas, and a passivation layer can be generated at the side wall, so lateral erosion on the GST material is avoided, and a GST graph with a steep side wall is obtained.