Conventional water-swelling gels lack re-crosslinking ability，making them susceptible to displacement from loss zones under pressure fluctuations，which reduces their pressure resistance and leads to poor plugging performance. Aiming at these problems，a self-healing gel was synthesized using chitosan as a physical crosslinker，combined with acrylamide（AM），acrylic acid（AA）and stearyl methacrylate（SMA）monomers. The gel’s structure was characterized through infrared spectroscopy， thermogravimetric analysis and scanning electron microscopy. Its swelling capacity，rheological properties，self-healing ability， compatibility with base fluid，and plugging performance were also investigated. Furthermore，the self-healing mechanism and plugging mechanism of the gel were analyzed. The results showed that the gel exhibited a spongy dual-network structure，with multiple non-covalent interactions including hydrogen bonding，electrostatic forces and hydrophobic associations within the network. The gel showed excellent water-swelling properties， which enhanced with increasing temperature. The swelling equilibrium value at 120 ℃ was 37 times higher than that at room temperature. After self-healing at 90 ℃，the gel particles exhibited a high storage modulus（3500 Pa）and a structural recovery rate（83%），while maintainined self-healing properties at 120 ℃. The compatibility between gel particles and base fluid was good. As the concentration of gel particles increased，the apparent viscosity of base fluid rose，while the fluid loss decreased. At a mass-volume ratio of 2%，the gel could meet the plugging requirements during drilling porous loss zones with simulated sand particles greater than 20 mesh（0.85 mm）. The self-healing mechanism of gel primarily relied on non-covalent bonds in its network structure，which broke and re-formed rapidly after damage， restoring the gel’s integrity and functionality. In terms of plugging mechanism，the gel particles migrated，accumulated and compressed within the loss channels，forming tight contact with the formation. The non-covalent interactions enabled self-healing and strong bonding with the formation，creating a durable gel-plugging layer. This self-healing gel showed potential application in enhancing drilling fluid loss control.