In this manuscript, a novel thermo/pH/magnetic-triple-responsive nanogel was synthesized based on (2-dimethylaminoethyl) methacrylate as pH-sensitive monomer and N-isopropylacrylamide as temperature-sensitive monomer grafted onto sodium alginate, as a biocompatible polymer. Iron oxide nanoparticles as magnetic nanometer base, ammonium persulfate as an initiator, N,N-methylenebisacrylamide as a crosslinker, and sodium dodecyl sulfate as a surfactant were employed for the provision of entitled iron oxide nanoparticles-nanogels in aqueous solution. Simply by regulating the sodium dodecylsulfate amount during polymerization, the size of nanogels could be finely controlled. The structural, morphological, and magnetic properties of the optimized sample were characterized by DLS, SEM-EDAX, AFM, TEM, FT-IR, TGA, and VSM. The procured nanogel displayed excellent reversible transmittance changes in response to pH and temperature. The release rate of doxorubicin as an anticancer drug from the nanogel was studied at different pH and temperature in the presence and absence of magnet.