Abstract: In this paper,the idea of co evolution is applied to the optimization of retaining and protecting structure for deep excavation,and the system of optimization of anchored piles in row has been developed successfully.For the co evolution algorithm provides an evolutionary mechanism to simulate everchanging problem space,it is an optimization algorithm that is highly effective,especially to be applied to the optimization of complicated system of retaining and protecting for deep foundation pit.It is shown by engineering practice that the co evolution algorithm has obvious optimization effect,so it can be an important method of optimization of retaining and protecting for deep foundation pit.The authors discuss the co evolution model, object function,all kinds of constraint conditions and their disposal methods,and several key techniques of system realization.