In order to prepare environmentally friendly coatings with radiative cooling performance in the middle and low-temperature domain (below 150°C), this paper first prepared a water-based adhesive. The preparation and test methods and results are as follows. The siloxane-coated cadmium telluride composite particles were prepared, and the surface layer was modified by amination with silicone coupling agent KH550. The modified composite particles were used to crosslink waterborne polyurethane to prepare waterborne adhesive and waterborne radiation coating. The composite particles and their modified aqueous emulsion film were characterized by XRD, FT-IR, TEM, TGA, and universal tester. Besides that, three kinds of water-based adhesives with different cadmium telluride content were prepared into radiation-cooling coatings and coated on steel plates. The temperature was raised to 70°C together with the uncoated steel plates, and then the temperature was lowered naturally. The cooling time of 4 steel plates to 30°C was recorded. The results show that the composite particles are microspheres, uniform in size and narrow in distribution. The radiation coatings prepared with three kinds of binders have good cooling and radiation performance, and the cooling performance increases with the increase of cadmium telluride content in the coating.