In the present work, the computational analysis of laminar, incompressible separated flow over a backstep is introduced by solving the incompressible Navier-Stockes equations. The technique of vorticity transport equation and Poisson equation are used to calculate the velocity through the domain, then the Poisson equation for pressure is used to get the value of the pressure all over the domain. Obtained data are graphically presented. Smoke wind tunnel is used to trace the flow streak lines around a finite length flat plate with backstep. Qualitative comparison between calculated and experimentally obtained traces showed good agreement.