In this paper, steel plate shear wall strengthened by Carbon Polymer's Fiber was studied. An equation has been proposed for elastic strength using composite theory and maximum work failure model, and another equation has been obtained for elastic displacement related to polymer's fiber using virtual work principle. Considering fibers and shear wall web as a layer and super positioning plate and fiber behavior, composite shear wall model was achieved. Optimum fiber orientation angle for composite shear wall was in diagonal tension field. Finite element values via the presented model were compared and concluded that the offered model can predict composite shear wall in close range. The proposed model can predict the elastic strength and displacement of composite steel plate shear wall that strengthened with CFRP layers. In this model, the over strength due to CFRP layers super positioned to PFI model and the overall response of composite shear wall can be achieved.