To improve connectivity-reliability of gas pipeline network the possibility of gas pipe network with intermediate state before failure is expounded.Based on the improved two states with safety and failure of pipe unit,a three-stage connectivity reliability work mode of safety-intermediate-failure is established.Through adopting hierarchical exploded mode of full probability,multi-loop gas pipe network with bridge circuit can be broken down into several simple compound pipe systems for reliability vector solving.The influence of correlation parameter among pipe units to connectivity reliability of gas pipe network is considered and the trust in connectivity reliability calculation is increased in this paper.