The averaged binding energy, energy gap, atomic charge and total charge density of the MgO nanotube clusters were calculated with B3LYP method at 6-31G（d） level. The calculations show that the everaged binding energy decreases approximately linearly with increasing coordination. The structural stability increases in company with length of MgO nanotube clusters, and the most stable structure is 3MR species. The charge transfer increases with length of MgO nanotube clusters, the averaged atomic charges of 2, 3 and 3 converge to 1298, 1270, 1306, respectively. Mixed covalent and ionic bonding property always exist in MgO nanoclusters.