Abstract: Firstly, polysarcosine-co-poly(L-glutamate-hydrazone) (PSar-co-PGH) was synthesized through ring opening polymerization of sarcosine N-carboxyanhydride (Sar-NCA) and γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) and followed by ester-amide exchange reaction. Then, sodium alginate (ALG) was oxidized by NaIO₄ and oxide sodium alginate (ALG-CHO) was obtained. Finally, hydrogel was prepared by mixing of PSar-co-PGH and ALG-CHO aqueous solution. The structure of polymers was characterized by Nuclear Magnetic Resonance spectroscopy (¹H-NMR), Fourier Transform Infrared spectroscopy (FT-IR), and the hydrogel mechanism and properties were characterized by Scanning Electron Microscopy (SEM), FT-IR and rotational rheometer, respectively. The effect of pH on the hydrogel formation was discussed. Results showed that the responsive hydrogel based on PSar-co-PGH/ALG-CHO was successfully prepared, and the store modul of the hydrogel increased with the increase of PSar-co-PGH concentration.