Based on first-principles plane-wave ultrasoft pseudopotential density functional theory method,the lattice structure, formation energy, density of states and charge density of the ZnO:(Mn,N) system are calculated and studied theoretically. Results show that Mn and N co-doped ZnO system is more suitable for doping into a p-type system, for it has a lower impurity formation energy and higher chemical stability; Mn and N in a proportion of 1:2 doping system can effectively reduce the formation energy of the system and so it is more stable; when the system forms a double acceptor level defects, the p-type characteristic of the system is more obvious, for the solubility of impurities and the number of carriers in the system are increased. In addition, it is found that more impurities can go through the Fermi level density of states in the Mn-N co-doped system, while the 2p state density of N is widened and effective mass of holes is smaller and more delocalized.Moreover,compared with the Mn-N-doped system, the density of states of Mn-2N co-doped system is more dispersed near the Fermi level, and the non-localized characteristics are distinctive, thus it is expected to be a more effective means of p-type doping.