Based　on　the　component　importance　and　reliability　of　public　transport　network,　the　node　importance　and　road　unit　importance　are　analyzed　to　improve　the　operation　of　public　transport　network.　Using　the　integrated　benefit　of　the　system　as　optimization　objective,　and　traveling　time　as　restriction,　an　optimum　model　of　public　transport　network　is　built.　Then,　an　example　is　given　to　illuminate　the　network　adjustment.　It　makes　a　higher　public　transport　system　reliability.