The geometric structure and electronic structure of (n, m) chiral singled walled ZnO nanotubes (NTs) have been calculated adopting first-principles calculation methods based on density function theory. The energy calculated results show that the binding energies of (n, m) chiral ZnO NTs are negative values, indicating (n, m) chiral ZnO NT is able to exist steadily. With the increase of pipe diameter for ZnO NTs, the total energy decreased and band gap increased gradually, and the system tends to more stable. The calculated results of electronic structure show that (n, m) chiral ZnO NTs are a direct wide band gap semiconductor, with valence band top mainly composed of O 2p states and conduction band bottom mainly composed of Zn 4s states. Moreover, intense interaction between Zn 3d and O 2p appears in energy zone from -6.3 eV to 0.0 eV, characterized by apparent hybridization of sp3 and sp2, which plays a key role in ZnO NTs with stable configuration.