The adsorption of N2 molecules on the basal plane of graphite was computer simulated by the canonical (CMC) and grand canonical (GCMC) ensemble Monte Carlo methods. The dependence of the average energy of adsorption on coverage obtained by the CMC method coincides with the results of independent molecular dynamics simulations. The isotherm of adsorption obtained by the GCMC method is close to the experimental data. The small deviations of the simulated isotherm from the experiment in the submonolayer region may be explained by the residual heterogeneity of the real surface of graphite. The deviation in the region of the second layer is probably due to the many-body interactions which were not properly taken into account in the computer simulations The results for the rigid nonspherical model of N2 are compared to those for a spherical model.