This paper presented the general methodology of quantitative analysis for Disaster based SDH/ATM bidirection self healing ring network survivability performance

and derived the survivability function in closed form for SDH/ATM Bidirection Self Healing Ring （BSHR） under link and node failures and multiple failures.Various single value survivability measure such as the worst case survivability and expected survivability etc.can be easily obtained from the derived survivability function.The analysis of the result of derived survivability function show that the methodology in this paper is feasible for analyzing large scale disaster based survivability and designing cost effective high survivability communications network.