Abstract. We introduce a new method for following the formation and evolution of galaxies in the cosmological N-Body simulations. Dissipationless simulations are used to track the formation and merging of dark matter haloes as a function of redshift. Simple prescriptions, taken from semi analytic models of galaxy formation are adapted for gas cooling, star formation and various feedbacks. This scheme enables us to explore clustering properties of galaxies, and to study how the selection by luminosity, colour and type influence the results. We plan to apply this model to the reionization study of the Universe at high redshift.