This study describes the detailed investigation on dynamic swelling of biodegradable network system poly(N-isopropylacrylamide-co-N-maleylgelatin) P(NIPAAm-co-N-MAGEL) prepared by N-isopropylacrylamide (NIPAAm) and N-maleylgelatin (MAGEL) with N,N′-methylene bis(acrylamide) (BIS) as a cross-linking agent. Effects of MAGEL content on the swelling behavior were investigated. The results showed that the swelling kinetics were dependent on the content of MAGEL and the maximum swelling rate was observed at 30% content of MAGEL. The swelling process follows second-order kinetics, and the mechanism of water transport is pseudo-Fickian type of diffusion. Swelling kinetics under different concentrations of NaCl was also studied. The swelling rate decreased with increasing the concentration of NaCl. Graphical abstractThe swelling rate of P(NIPAAm-co-N-MAGEL) hydrogel can be tuned by MAGEL content and NaCl concentration.