A protein-polysaccharide hydrogel was reported as a biocompatible, biodegradable, and non-toxic material that had biomedical applications such as drug delivery. The hydrogel, composed of 10% casein and 1% konjac glucomannan (KGM), was formed with 0.4 wt% transglutaminase (MTG) as the cross-linker. The physicochemical properties of the protein-polysaccharide hydrogel were investigated by SEM observation, FT-IR analysis, swelling ratio test, and stability test. The results of the stability test proved that the hydrogel with KGM had an obviously improved stability. Its degradation rate also decreased from 100% to less than 60% compared with the hydrogel without KGM at the end of the test. The results of the swelling ratio test demonstrated that the addition of KGM restricted the mobility of the chains, and decreased the swelling ratio of the hydrogel. The results of the FT-IR revealed hydrogen bond interactions during the gelation process upon the addition of KGM. To investigate in vitro release behavior, docetaxel was chosen as a model drug incorporated into the casein/KGM hydrogels. The hydrogel with 1% KGM exhibited a good drug release behavior.