Abstarct: Forming and separation of a drop which is falling in to another fluid is among on the complicate and interesting issues in dynamic fluid science, various application of this phenomena in different issues including medicine production, powerhouses, surfaces coating, cooling, atomization etc had interested many researchers in improving and increasing industrial products, therefore in the present research viscoelastic drop formation in the air was investigated numerically ,in the present research volume of fluid method has been used for simulation in determining common surface between two phases and on linear Giesekus model ,the equations in this solution in an asymmetry has been solved by openfoam software and non dimensional numbers effect including Bond number, Capillary number, viscose ratio, mobility factor and Wiesenberg number to viscoelastic drop formation was also investigated. Obtained result comparison of numeric solution with available numeric and laboratory data indicates that obtained results have accuracy and reliability. In the initial stage of drop formation when viscous force is still weak, the dynamics are controlled by a balance between inertial and capillary forces, and there is no contribution of elastic stresses of the polymer. This is while in the final steps of drop formation mobility factor changes and viscosity ratio and Wiesenberg number has a significant effect on drop formation dynamics. Performed research indicates that by the non-dimensional number increase, mobility factor and viscosity ratio ,filament narrowing of drop, rapid separation performed and drop pinch off length and primary drop volume decrease too. As the obtained results show drop pinch off length changes has direct relationship with non-dimensional Bond number and Capillary but the primary drop volume with non-dimensional Bond and Capillary numbers have a reverse relation.