Abstract: The invention discloses a thermosensitive modified chitin hydrogel local anesthetic-loaded sustained-release analgesia system, a preparation method and use. A thermosensitive chitin derivative is dissolved into water at a low temperature, a local anesthetic and analgesic drug aqueous solution or degradable polymer microspheres loaded with local anesthetic and analgesic drugs are added under a liquid state, the above materials are evenly mixed at a low temperature, the obtained mixture is injected into a site needing local anesthesia and analgesia so as to quickly form a gel under a body temperature and release the drug. The local anesthetic drug sustained-release analgesia composite hydrogel system is mainly characterized in that preparation is simple, organic solvents are not used, the local anesthetic and analgesic drug can be slowly released, and the problems that the existing local anesthetic drugs have a short action time are solved partly.