Taylor-Couette flow with two independently counter-rotating cylinders is investigated. Direct numerical simulation is applied to study flow structure and angular velocity transport for η = 0.714 at optimum and fully turbulent regime. The main purpose is to study the coherent structure in both axial and radial directions and its contribution to angular velocity transport in optimum condition. Visualizing the vortical structure (and other structural parameters) with the distribution of azimuthal velocity and ω-Nusselt number leads to a better understanding of turbulent flow structure at optimum condition comparing to non-optimum condition.