Abstract: The flexural behavior, elastic and properties of steel fiber reinforced geopolymer mortar were experimentally investigated in this study. Geopolymer mortar mixes were arranged by low calcium fly ash and it is activated by using (NaOH and Na2SiO3) alkaline solutions with 0.4 ratio from fly ash solution. Alkaline activator is prepared by mixing of 10 molarity of NaOH solution with Na2SiO3in 1:2.5 ratio. Steel fibers were added at various volume of fractions for the geopolymer mortar of (0-3%) at an interval of (0.25%) by mix volume. Effectiveness of steel fiber content was assessed according to properties of geopolymer mortar such as (workability, fresh unit weight, flexural, compressive and splitting tensile strengths) and the flexural behavior of thin ferro geopolymer slab with welded square wire mesh is presented. Test results showed that steel fiber enhanced the mechanical properties of geopolymer mortar, particularly for the flexural and splitting tensile strengths. As well as adding steel fibers improved the flexural resistance of ferro geopolymer slab 2.25% increased the load capacity with 155.59% and decreased in deflection 75.18% as well as caused delay in crack growth and crack width is decreased, however, number of cracks is increased. Using steel fiber in ferro geopolymer slabs increased the ductility of because of introduction of steel fiber in the mix.