A platinum polymer catalyst (Pt-PDMS) was synthesized by immobilization of a platinum catalytic complex in a polysiloxane chain using an azide–alkyne CuAAC cycloaddition. Insoluble Pt-PDMS can be used as an effective heterogeneous macrocatalyst for Si–O dehydrocoupling. Pt-PDMS is easy to recover, purify, and reuse again for heterogeneous catalysis.