The selection of attenuation parameters affects the accuracy of measurement directly in the laser damage testing system.In this paper,the genetic algorithm has been improved,the real number encoding using parameter encoding,fitness sorting and randomly selected with random selection operator,cross two is bound to have a cross section of the individual genetic crossover operator,mutation operator according to the size of a crossover operation on the individual Using the improved algorithm,3 sets of 15 pieces of attenuator for mechanical laser energy attenuator are optimized.The optimization results show that:the attenuation rate of 8 different attenuation rates is selected in the 15 pieces of attenuator,and the energy decay rate interval is less than 3 % of the maximum laser energy,and the linearity error is about 12.4 %.