Cellulose nanocrystals are considered as promising biomass nanofillers for polymeric hydrogels, but poor interface compatibility between cellulose nanocrystals and hydrogel matrix usually reduces their reinforcement effect. Here, we reported a novel interface compatible nanocomposite hydrogel prepared by introducing quaternized tunicate cellulose nanocrystals (Q-TCNCs) into chemically cross-linked poly (acrylic acid) (PAA) networks. Q-TCNCs acted as both nanofillers and physical cross-linkers in the PAA networks, and the electrostatic interaction between the positive charges of Q-TCNCs and negative charges of PAA chains improved their interface compatibility. The nanocomposite hydrogels exhibited controllable swelling ratio and pH-sensitive swelling behaviors. The mechanical properties of hydrogels significantly increased after incorporation of Q-TCNCs. Moreover, the nanocomposite hydrogels exhibited partly recoverable ability due to the presence of reversible electrovalent bonds in the hydrogel networks.