Nb thin films have been prepared by electron beam evaporation under ultrahigh vacuum conditions on fused silica substrates at various temperatures, and their structural and morphological evolutions have been investigated using X-ray diffraction and atomic force microscopy. The crystallographic texture of the Nb films is found to depend on the growth temperature. At room temperature, the [110] texture is dominant. However, at 200 degreesC, the [310] oriented growth is favored, co-existing with [110] and [200] oriented grains. At 400-600 degreesC, a completely [110] textured film is formed. At even higher temperature (800 degreesC), a complex texture of [110] (dominant), [200] and [310] is observed again. It is also found that the single [110] textured Nb films have smooth surfaces, and the complex textured Nb films have rough surfaces.