Abstract-In the using of materials, kinds of injury which is sometimes difficult to repair or too costly to repair may appear in the surface and interior, which will shorten the life of the materials. Self-healing technology can be used to improve material reliability and extend the service life, so composite materials with self-healing capability become an important research content of smart materials. Selfhealing materials can perform self-diagnosis after suffered from external forces and repair the crack or damage in a certain degree. According to the healing agents applied or not in the self-healing process, self-healing methods in polymer materials can be classified into extrinsic selfhealing and intrinsic self-healing. Based on the latest research achievements, several typical extrinsic selfhealing methods are summarized, including microcapsule self-healing, hollow-fiber self-healing and microcapsule self-healing. Several repairing mechanisms, self-healing system characteristic, existing problems and present research status are elaborated. Future research on selfhealing materials is prospected, optimizing and developing new healing agents system in order to improve the selfhealing efficiency and realizing the true smart materials.