Abstract: In this paper, the optical channel frame is presented to load data and the technology of SDH over WDM is utilized to improve the survivability of the WDM ring networks. The method has the character of realizing highly effective transmission via utilizing the extant facilities and the network management. Based on the analysis of the transmission characters of the ring networks that have self-healing function, a method of establishing mathematical model is discussed, and the relationship of the average rejection probability and the traffic is obtained.