本文根据实际的光功率概算参数分布,用统计法对140Mbit/s单模光纤系统的中继距离进行了设计。结果表明,当系统先期失效率为0.1％时,按统计法设计的最大中继距离可以比传统的最坏值法加长17公里。进而,我们还提出了一种简化的统计设计法,可以避免完全统计法的计算复杂性,同时又保留了其主要优点。 In this paper, according to the actual optical power budget parameter distribution, using the statistical method to design the 140Mbit / s single-mode fiber system relay distance. The results show that when the system failure rate is 0.1%, the maximum relay distance designed by statistical method can be extended 17 kilometers longer than the traditional worst value method. Furthermore, we propose a simplified statistical design approach that avoids the computational complexity of complete statistics while retaining its main advantages.