This paper investigates the electromagnetic transmission through the sub-wavelength slot model on a metal film for TM- and TE-polarized light. The influence of several parameters such as the slot width, the metal film thickness and the polarization of the incident field is investigated using FDTD method. The FDTD simulation’s results have shown that the sub-wavelength slot in the metal films has extraordinary optical transmission (EOT) properties for TM-polarized light. The EOT has been observed as being symmetrically punctured and characterized by the appearance of a series of transmission peaks and dips in the transmission field. By varying the slot thickness we have investigated the effect of the Fabry-Pérot like resonance in the sub wavelength slot. This component can be a key element in many applications. High-spatial-resolution imaging and information and communications technologies and sensing with high spectral and spatial precision, enhanced solar cells, efficient optical sources and detectors, disease treatment, are such examples.