A novel phenylboronic acid ionic liquid (PBA-IL) monomer was designed, and the self-healing hydrogel (PAM/PBA-IL/CNF) with semi-interpenetrating network was prepared by a one-step polymerization of acrylamide (AM) and PBA-IL in the presence of TEMPO-oxidized CNFs. The chemical structure of PBA-IL was analyzed by 1H NMR. The chemical structure and physical morphology of the hydrogel were characterized by FTIR, XPS and SEM. The mechanical properties and self-healing properties were tested by tensile test and self-healing experiment. The results showed that the PBA-IL monomer and the hydrogel were successfully prepared, and the hydrogel exhibited excellent self-healing properties. When the mass fraction of PBA-IL was 30%, the self-healing efficiency of PAM/PBA-IL3/CNF hydrogel was 95.43% (within 150 min). And the tensile strength (319.5 kPa) and elongation at break (1950.3%) of the self-healed PAM/PBA-IL3/CNF hydrogel approached that of the original hydrogel. The self-healing properties of PAM/PBA-IL/CNF hydrogels were attributed to the synergistic effect of the boronate bonds formed by the PAM/PBA-IL copolymers with the cis-diols on the CNFs chain and the multiple hydrogen bonds inside the hydrogels.