Abstract: Laser cladding is an advanced technology to improve surface properties, which is widely used in aviation, automobile, petroleum and other industries.As the most troublesome defect in the process of laser cladding, the cracks seriously reduce the quality of the cladding layer and greatly limit the industrialization of laser cladding technology.The types and mechanism of cracks were summarized, and the calculation formula of the stress resulting in cracks was exemplified, and then the cracks were controlled from the aspects of process parameters, cladding materials and auxiliary fields.Finally, the existing problems in the current research and the future research and development direction were analyzed.