The invention discloses adhesive resin for a barrier composite hose and a preparation method and application thereof. The preparation method comprises the following steps of: firstly dissolving the following materials in parts by weight: 0.1-0.5 part of initiating agents, 1-3 parts of maleic anhydride and 0.5-1.5 parts of acrylamide into acetone, then uniformly mixing with 100 parts of PE, and carrying out reactive extrusion to obtain a maleic anhydride and acrylamide double-monomer grafted PE master batch; then carrying out blending extrusion on the following materials in parts by weight: 20-30 parts of the PE master batch, 50-70 parts of linear low density polyethylene, 10-20 parts of polyolefin elastomers, 0.05-0.15 part of fluoropolymer processing auxiliary agents and 0.2-0.5 part of antioxidants for granulation to obtain the adhesive resin for the barrier composite hose. The adhesive resin disclosed by the invention forms a transparent granule with a natural color in appearance, is stable in property and few in eutectic points and achieves the stripping strength on adhering to EVOH more than 250 N/cm. The barrier composite hose prepared by using the adhesive resin has the advantages of good adhesive property of various layers, high barrier property and smoothness of inner and outer surfaces.