In this work,nanostructured silicon dioxide films are deposited by closed-field unbalanced direct-current (DC) reactive magnetron sputtering technique on two sides of quartz cells containing rhodamine B dye dissolved in ethanol with 10-5 M concentration as a random gain medium.The preparation conditions are optimized to prepare highly pure SiO2 nanostructures with a minimum particle size of about 20nm.The effect of SiO2 films as exteal cavity for the random gain medium is determined by the laser-induced fluorescence of this medium,and an increase of about 200％ in intensity is observed after the deposition of nanostructured SiO2 thin films on two sides of the dye cell.