Abstarct: The non-dimensional forms of Navier-Stokes equations for two dimensional plane duct flow are solved using direct numerical simulation. The length scale and the velocity scale of the baxse flow at the inlet boundary of computational domain are used as two characteristics to define the flow Reynolds number. These two characteristics are the duct diameter and the maximum velocity or velocity at the centerline in cross section. The governing equations are discretized in streamwise using a sixth order compact finite difference scheme and cross stream direction using a mapped compact finite difference scheme, respectively. A mapping is used to relate the physical domain to the computational domain. The third order Runge-Kutta method is used for the timeadvancement purpose. The numerical results show a very good accuracy and agreement with the exact solution of the Navier-Stokes equation. Results in self-similar coordinate were also investigated which indicate that the time-averaged statistics for velocity and vorticity tend to collapse on top of each other at the flow downstream locations. The pressure distribution is found by Navier-Stokes equation, which must reaches to a constant value related to the flow Reynolds number in fully developed region. The result of pressure analysis shows a good agreement with this exact solution.