Abstarct: Boundary laxyer flow is considered as one of the fundamentals in fluid mechanic Engineering, so it has been attended by researchers for a long period. Up to this day a great number of investigations have been done focusing on this subject that most of them have been about Newtonian Fluids and just a few numbers of them have been out of this circle and about viscoelastic fluids. Main purpose of this research is to better understanding of viscoelastic effect on boundary laxyer characteristics. In this research, we investigated boundary laxyer made by viscoelastic flow on a flat plate using both numerical and analytical approaches. In numerical approach, we used OpenFOAM software which is a Calculation Fluid Dynamics tool box (CFD) to simulate this flow. this software uses finite volume method (FVM) to solve equations using Partial derivatives. we also applied Giesekus model in our numerical solution as constitutive equation. Then to be able to trust on numerical method outcomes, result independencies have been investigated. Also, results in Newtonian fluid have been compared with Blasius solution. We used "Von-Karman" integral baxsed method basics which is a Approximate method in Newtonian boundary laxyer studings in analytical approach,. We tried to generalize this method to viscoelastic fluids. Results obtained by both methods illustrated making a limited thickness at the leading edge (x=0) because of elastic effects in viscoelastic fluids. Numerical approach illustrated that increases in elastic number decreases shear stress and normal stress differences and also drag coefficient was reported in different elastic numbers.