MgxNi1-xO (x = 0.25-0.56) thin films were fabricated by radio frequency (RF) magnetron sputtering on a quartz substrate. The influences of different Mg contents on the bang-gap of MgxNi1-xO thin films have been studied. XRD measurements indicate that the MgxNi1-xO films are of cubic NiO structure with a (111)-preferred orientation. UV-visible transmission spectra show that the absorption edges of thin films shift to short wavelength with increasing Mg content. The band-gap is already in the solar-blind region when the Mg content in the film is 46%. XPS results showed that typical sosoloid of MgxNi1-xO has been prepared without obvious phase separation. The result implies that MgNiO is a promising candidate material for solar-blind UV detection. (C) 2011 Elsevier B.V. All rights reserved.