Dextran-based nanogel with Schiff base structure were prepared by the inverse microemulsion technique, and its functions as drug carrier was studied using HPTS as model drug, which was loaded via the electrostatic adsorption with polyethyleneimine (PEI, crosslinker). The structure of dextran nanogel was characterized by FTIR、SEM and DLS. The dextran nano-hydrogel has a good spherical structure before and after drug loading, and the particle size is mainly distributed at about 459~648 nm. HPTS can be effectively loaded into the dextran nanogel and showed an obvious acidic environment sensitive release behavior. The stronger the acidity, the faster the drug released. The dextran nanogel with Schiff base structure can be used as a pH-sensitive drug delivery system.