The invention discloses a method for obtaining the surface contact ratio of an acid etching fracture by an experiment measure. The method comprises the following steps of: (A) respectively cutting white paper and carbon paper which have the same surface shape and size as an original rock plate; (B) sequentially putting the white paper, the carbon paper and the rock plate subjected to acid etching on a smooth steel plate; then putting a rigid press head onto the rock plate; exerting preset pressure on the rigid press head; and performing stabilization for one minute; (C) unloading the pressure (a mark of the contact area between the rough surface of the rock plate and the steel plate is left on the white paper by carbon paper); (D) dividing the total pixel of the whole paper by the pixel of the mark part to obtain the contact ratio between the rock plate and the steel plate; and (E) multiplying the contact ratio by 20.25 to obtain the contact ratio of the two rock plate surfaces corresponding to the rock plate under the mutual contact condition. The method has the advantages that the principle is reliable; the operation is simple and convenient; and the accurate contact ratio data can be provided for the study of the acid etching crack flow guide capability.