In this paper, we analyzed the guiding problem for dielectric waveguide introduced as defect layers composed of dielectric circular cylinders with rhombic dielectric structure along a middle layer, and investigate the distribution of energy flow of dielectric waveguides for both TM₀ and TE₀ modes by using the propagation constants at the guided area. From numerical results, we can be obtained the confinement efficiency by loaded with rhombic dielectric structure compared with dielectric triangular cylinders for TM₀ mode. In the case of TE₀ mode, it is shown obviously that we can be obtained the confinement efficiency loaded with dielectric circular cylinders compared with rhombic dielectric structure.