Abstract: In this research, the optical characteristics of thin films of a laser dye Rhodamine 110 doped with PVC which prepared using the casting method at room temperature were studied. The solution of (10, 20, 30, 40 and 50%) molar ratio of Rhodamine 110 solution was mixed with fixed amount of PVC solution, the mixture casting on the glass sample at room temperature for 24 h to obtain the final thin film. The absorption spectra were studied at a range of wavelength (190-1100 nm) by (UV-VIS) beam spectrometer for all samples. Optical constants were calculated such as the absorption coefficient (α), index coefficient (n) and extinction coefficient (k) for all samples. The concentration of laser dye effect on the allowed direct and indirect energy gaps where the increasing in dye concentration leads to decreasing in both these energy gaps. Also, it can deduce that the optical properties of the prepared samples changed by varying the molar ratio of the laser dye.