Chromium (Cr) thin films with thickness ranging from 5 nm to 114 nm were deposited on quartz substrates by the direct current magnetron sputtering. X-ray diffraction and optical spectrophotometer were employed to characterize the crystal structure and optical properties, respectively. Based on the Drude optical dielectric model, optical constants and thicknesses of the films were calculated from the transmittance and reflectance data. The sheet resistance was measured by Van der Pauw method. The results show that the films have a body-centered cubic crystalline structure. The grain size of the film increases gradually and the crystalline performance enhances as film thickness increases. When film thickness is less than 32 nm, transmittance decreases sharply, reflectance and extinction coefficient increase rapidly as the increase of thickness. When thickness is larger than 32 nm, both refractive index and extinction coefficient decrease gradually until they become stable as the thickness increases. Resistivity is the first order exponential decay when thickness increases from 5 nm to 114 nm.