The invention discloses a triazole-based polyhedral oligomeric silsesquioxane copolymer and a preparation method thereof and relates to a polyhedral oligomeric silsesquioxane polymer with a plurality of active coordination sites. The copolymer and the preparation method are characterized by fully utilizing the advantages of efficiency, mild condition and fast reaction of Click chemistry, and combining an RAFT (Reversible Addition-Fragmentation Chain Transfer) active polymerization method to prepare the polyhedral oligomeric silsesquioxane copolymer with a plurality of nitrogen coordination sites. The 1,2,3-triazole-based polyhedral oligomeric silsesquioxane copolymer prepared by the method disclosed by the invention has potential application in the aspects of medicine carrier, metal ion sensor, adsorption separation material and the like.