Display omitted •A chitosan/CNC/PAAm hybrid hydrogel is developed via double-network.•The hydrogel has superior tensile and compressive properties.•The hydrogel exhibits high self-recovery rate (81.3% after 12 h at room temperature).•The hydrogel is biocompatible and have potential for controlled drug release. As medical practitioners’ interest in hydrogels continues to grow, their new expectations in terms of mechanical properties, biocompatibility and durability are changed. Here, we demonstrated a new strategy to improve both mechanical properties and self-recovery of double network (DN) hydrogels by introducing a self-healing network, consisting of carboxymethyl chitosan (CMC) and dialdehyde cellulose nanocrystals (DACNC). Notably, the hydrogel could be repeatedly stretched to 4 times its initial length and has tensile strength of 244 kPa, and completely recovered its shape when compressed by 90% and had the compressive strength up to 8 MPa. In addition, the deformed hydrogel recovered 81.3% of its dissipated energy at room temperature without any external stimuli. The hydrogel also exhibited good biocompatibility. We have developed a new method to fabricate stretchable and tough hydrogels that could spontaneously self-repair following mechanical deformation. They are promising for controlled drug release and dye adsorption.