Deformation of the shadow mask is one of the problems encountered during the deposition of organic materials for manufacturing large size organic light emitting diode (OLED). The larger the glass substrate, the larger the shadow mask becomes. As the size of the shadow mask increases, its deformation becomes more severe, thereby making it difficult to deposit organic materials in a precise pattern on a substrate. In this paper, a new method for reducing drooping of the shadow mask for large size OLED vapor depositions is proposed. The proposed shadow mask with cross stripe wires has higher stiffness than the pure shadow mask, which results in reducing drooping of the shadow mask. A commercial FEM program, ANSYS, is used for the evaluation of the proposed shadow mask. The analysis showed that the shadow mask with cross stripe wires have an effect on reducing drooping about 18.6% or more.