In order to study iteration searching properties of intelligent optimization algorithms parameters in dispersion equations of different crystal material, genetic algorithm, simulated annealing algorithm and genetic simulated annealing algorithm were employed, respectively, to obtain the coefficients of the improved Sellmeier equation for quartz crystal and calcite crystal according to the measured experimental data.Meanwhile, the differences of iteration searching property, algorithm stability, computation time and sum of squares of deviations in the three algorithms were compared.The results show that the three algorithms are all feasible in terms of coefficients retrieval in the dispersion equation, however, genetic simulated annealing algorithm have rapid large-scale search and strong local search performance deriving from the genetic algorithm and simulated annealing algorithm respectively.It makes optimization results of crystal dispersion equation parameters in inversion to be better.Therefore, we recommend using the genetic simulated annealing algorithm to obtain dispersion equations for other materials.The aforementioned results are of help to the study of iteration searching properties of mixed intelligent algorithms.