In the present work, high quality nanostructured thin films of titanium nitride with nanoscale grain sizes have been prepared by the reactive magnetron sputtering method examining the effects of the substrate temperature on the topography, optical and semiconductor properties of the thin films Concretely, the three dimension surface topography of samples was investigated by atomic force microscopy determining the power spectral density functions. Also, a new revised version of the Tauc’s method (named ineffective thickness method) has been proposed for the determination of the optical band gap in nanostructure semiconductor thin films. These studies indicated that the increment of the substrate temperature improves the physical properties of the films modifying the grain size and grain aggregation, and altering the optical band gap of the samples from 4.06 to 3.43 eV. In addition, a competitive growth of crystalline planes with different orientations was found as a result of the occurrence of higher grain sizes in the nanostructured titanium nitride thin films.