Supporting structure of deep excavation is optimized using genetic algorithm（GA）;and limitation of GA such as poor local search ability and premature is largely enhanced.Then crossover operator and mutation operator is improved while considering the adaptive method;also the combination of hill-climbing with GA enables better local search ability in post-evolution.Mathematic model of deep excavation supporting structure is discussed;according to which a GA software system is developed for deep excavation retaining system.An engineering example is studied;and the results show the validity of the amelioration.