Many diluted magnetic semiconductor oxide systems exhibit interesting room temperature ferromagnetism, which has open the way for spintronics devices .Transition metal doped ZnO diluted magnetic semiconductor, has recently attracted intense research interest for the purpose of spintronics application. This research work deals with the theoretical study of feromagenetism in iron doped ZnO (Zn1-xFexO), diluted magnetic semiconductor DMS(x=0.25-0.3). A model Hamiltonian is formulated to describe the interactions between conduction electrons and localized magnetic moments, focusing on the Sp-d exchange interaction that plays a crucial role in the emergence of ferromagnetism. By developing a model Hamiltonian for the system and using the holistin pirmakoff transformation and Greens function formalism, we have obtained expressions for magnon dispersion relation, magnetization and Curie temperature (Tc). By employing the experimental values of the parameters in the obtained expressions, magnon dispersion relation versus temperature, and magnetization versus temperature and Curie temperature (Tc) versus concentration (x) are plotted separately. Our finding is in agreement with previous experimental findings.