A novel pHsensitive degradable hydrogel based on ethylenediaminetetraacetic dianhydride (EDTAD) was synthesized.EDTAD reacted with butanediamine through Nacylation ringopening polymerization of anhydride groups to give a linear copolymer (pEDTADBDA) with carboxyl groups on its side chains and amide groups on its backbone. pEDTABDA was dehydrated between those carboxyl groups on its side chains and amide groups on its backbone at 160℃ with phosphoric acid as a catalyst. A copolymer was produced containing imide groups (pEDTADBDAImide). pEDTADBDAImide was crosslinked by BDA via Nacylation of the imide groups, yielding the desired network polymer with pendant amino groups (BDAcrosslinkedEDTADBDA). BDAcrosslinkedEDTADBDA is a promising hydrogel for drug controlled release integrating such advantages as degradability, good biocompatibility and pHsensitivity. FTIR and ninhydrin reaction are employed to qualitatively and quantitatively characterize pEDTADBDA and BDAcrosslinkedEDTADBDA.