Click chemistry refers to the type of chemical reactions that occur between specific pairs of reagents, taking place under mild conditions with high stereoselectivity. These characteristics help chemists to construct very complex molecules in a relatively easy, quick, and precise manner. Polymers are widely used in daily life which are composed of repeating monomers. They can be designed and synthesized to meet certain characteristics to apply in real life. Click chemistry plays an essential role in creating new polymers, including modifying them afterwards. This paper introduces three typical click chemistry reactions in polymer synthesis and modifications, which include Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), thiol-ene reaction, and Diels-Alder reaction. They all have positive impact in synthesizing and modifying polymer. CuAAC reaction is applied to make desired polymer with crosslinking structure or other desired protein structure and modify the product by introducing new functional groups. Thiol-ene reaction makes good use in producing adhesives, including light-curing adhesive and bio-based adhesive, as well as surface modification. Diels-Alder reaction provides new insights in the synthesized polymers. At last, double click chemistry, which is still at the stage of preliminary exploration, contributes to creating complex polymers. The use of click chemistry in polymers is powerful and useful, leading the development of advanced materials and upgrading synthesizing skills.