系统可靠度的合理分配对整个系统的可靠性设计至关重要 ,而复杂系统可靠度优化分配所建立的非线性数学模型难以求解 ,针对这一问题 ,利用大系统理论的递阶协调策略的两种基本形式 :目标协调法和混合协调法 ,对便携式弧焊机器人系统可靠度的优化分配进行求解 ,取得满意的效果 ,由此证明递阶协调是一种非常有效的系统可靠度优化分配的求解方法 . The reasonable allocation of system reliability is very important for the reliability design of the whole system. However, the nonlinear mathematical model established by the optimization of complex system reliability is difficult to solve. In view of this problem, using the hierarchical coordination strategy of large system theory, The basic forms of this method are the target coordination method and the hybrid coordination method. The optimal distribution of the reliability of portable arc welding robot system is solved and the satisfactory results are obtained. It is proved that the hierarchical coordination is a very effective solution to the optimal allocation of system reliability Method.