Cylindrically symmetric inhomogeneous string cosmological model of the universe in presence of electromagnetic field is investigated. We have assumed that F_{12} is the only non-vanishing component of electromagnetic field tensor F_{ij}. The Maxwells equations show that F_{12} is the function of $x$ alone whereas the magnetic permeability is the function of x and t both. To get the deterministic solution, it has been assumed that the expansion ($theta$) in the model is proportional to the eigen value $sigma^{1}_{1}$ of the shear tensor $sigma^{i}_{j}$. Some physical and geometric prperties of the model are also discussed.