<p>This paper describes a comprehensive study of the dynamic behaviour of the&#xa0;fluid flow through two tandem elliptic cylinders with the various effects of designed parameters, particularly aspect ratios of both elliptic cylinders and spacing ratio (<i>L</i>/<i>D</i>). The aspect ratios of both the upstream (<i>AR</i>₁) and downstream (<i>AR</i>₂) cylinders vary from 0.25 to 1.00, <i>L</i>/<i>D</i> ranges from 1.5 to 10, and the Reynolds number of 100 is examined. The physical phenomenon corresponding to each flow regime is explained thoroughly. Additionally, a general 3D map of the vortex flow mechanism with four regimes (Overshoot, Reattachment, Two-layer vortex shedding, and Secondary vortex shedding) is first provided under the various effects of <i>AR</i>₁, <i>AR</i>₂, and <i>L/D</i>. Moreover, hydrodynamic parameters are dramatically and non-linearly dependent on these designed parameters<i>.</i> Based on an extensive study, the overall optimum range of all designed parameters at which the hydrodynamic parameters are minimized is first proposed. These results provide good guidelines for optimizing the configuration of two tandem elliptic cylinders used in potential engineering applications.</p>