CF-NH2-AZO-p(VPA-x) was synthesized by a “grafting from” radical polymerization approach. The phosphate group content of CF-NH2-AZO-p(VPA-x) could be easily regulated. CF-NH2-AZO-p(VPA-x)-Ti4+ was prepared and used for phosphopeptides enrichment. 3241 unique phosphopeptides were identified from 0.5 mg of rat brain by this method.