Abstract: The electromagnetic simulation based on Non-uniform FDTD mesh is a generalized and efficient method to solve many practical electromagnetic problems. In this paper a Non-uniform FDTD Mesh Generation System in Cartesian Coordinates is introduced, which visually makes FDTD grids with an user friendly interface. The system can quickly and efficiently generate 1D,2D,3D,FDTD meshes and demonstrate object geometry patterns.Furthermore,FDTD meshes can also be checked, adjusted and modified dynamically and visually. As a sample, meshes of a practical structure are produced and illustrated for validation.