In this work, TiNxOy thin film was deposited by a DC magnetron sputtering method as a function of oxygen flow rate. Changes of chemical states of constituent elements in the deposited films were examined by X-ray photoelectron spectroscopy analysis with the increased oxygen content. As the oxygen content increased, the peak positions of Ti2p shift to 459 (Ti2p12) and 464 eV (Ti2p3/2) with higher valence state, respectively. The film growth orientation and microstructural characteristics were also analyzed by transmission electron microscopy. The major part of the sample was amorphous TiNxOy and the minor part was TiN(111) crystallity as seen by HRTEM image and micro-diffraction pattern. The resistivities of TiNxOy thin films were varied up to 1010 Ωcm with increasing oxygen contents. Such results allowed us to understand the close relationships between the chemical states, microstructural characteristics and the resistivities.