The single band Hubbard model is considerably the simplest effective model that includes both the delocalizing/hopping energy and the on-site interaction for describing strongly correlated electron system. Despite the simple form, it is still yet challenging to find the solution to the model. Here we propose to investigate the energy spectrum of the compound NaCuF3 which could be a condensed-matter realization of the single band Hubbard model, as suggested by recent ab initio electronic structure method calculation.