Double-network (DN) hydrogel is consist of two intertwined crosslinked networks, with a balanced mechanical performance combining high strength and toughness. In addition to the excellent mechanical properties brought about by the double-network structure, it can also possess good anti-swelling and self-healing properties, laying a good foundation for the application of hydrogels in the environment. Recently, research on the application of double-network hydrogels in the environment has gradually increased. We classify this type of hydrogel in terms of composition and crosslinking methods, and discuss its adsorption mechanism for different environmental pollutants (metal ions, dyes, antibiotics). Finally put forward prospects for the preparation, environmental pollutant removal, and practical application of double-network hydrogels.