In this paper, the performance evaluation of first-fit, random, most-used and wavelength conversion algorithms in WDM optical ring network are being proposed. The blocking probability of various algorithms has been compared. The blocking probability is maximum for first fit algorithm and least for wavelength conversion algorithm nearer to 0.01 and 0.0025 respectively. So the performance of the wavelength conversion algorithms is best but there is burden of using expensive hardware. Without the need of wavelength-convertor, the most-used algorithm performs better than the random and first-fit algorithms. These approaches are very effective for the minimization of blocking probability of optical WDM networks.