The invention belongs to the technical field of water-stop belts and preparation methods, and discloses a coupling agent modified reactive macromolecular self-adhesive water-stop belt and a preparation process thereof. The coupling agent modified reactive macromolecular self-adhesive water-stop belt is mainly characterized by comprising a water-stop belt base material, wherein a modified macromolecular self-adhesive glue layer is arranged on the surface of the joint of concrete and two ends of the water-stop belt base material; an isolation membrane is arranged on the surface of the modified macromolecular self-adhesive glue layer; the modified macromolecular self-adhesive glue layer comprises the following components in parts by weight: 50-70 parts of a thermoplastic elastomer SIS (styrene isoprene styrene), 40-60 parts of tackifying resin, 2-4 parts of a coupling agent, 15-20 parts of a plasticizer, namely naphthenic oil, 2-5 parts of a coloring agent, namely titanium dioxide, 1-2 parts of an ultraviolet absorbent, 2-5 parts of fillers and 1-2 parts of an antioxidant. According to the coupling agent modified reactive macromolecular self-adhesive water-stop belt, macromolecular self-adhesive glue is modified with the coupling agent, and the modified macromolecular self-adhesive and structural concrete have not only a basic physical bonding effect but also a chemical bonding effect, so that the rubber base material and the structural concrete are firmly combined together and the bonding force is not reduced with the passage of time.