In order to improve the simulation accuracy of scroll compressors, a novel mesh-generation method of structured dynamic mesh (SDM) is proposed for fluid domains of scroll compressors in this paper. High-quality and density meshes are generated using the SDM in the fluid domains, especially in the flank meshing clearance between wrap profiles in the orbiting and fixed scrolls. The mesh generation process is presented, including scroll solid boundary of fluid domains, structured mesh dividing method in normal and tangent direction, and motion equations of each layer of nodes. Based on the SDM, numerical simulation of an unsteady compressible viscous turbulent flow with moving boundaries in the working process of scroll compressors is carried out, and the overall flow distributions of pressure, temperature and velocity are obtained. The study results show that the numerical simulation using the SDM is more accurate than using the existing unstructured dynamic mesh. The results are significant to predict, exhibit and reveal flow fields in the fluid domain of scroll compressors.