Background: High score of model for end-stage liver diseases (MELD) before liver transplantation (LT) indicates poor prognosis. Artificial liver support system (ALSS) has been proved to effectively improve liver and kidney functions, and thus reduce the MELD score. We aim to evaluate whether downgrading MELD score could improve patient survival after LT. Methodology/Principal Findings: One hundred and twenty-six LT candidates with acute-on-chronic hepatitis B liver failure and MELD score 30wereincludedinthisprospectivestudy.Ofthe126patients,42receivedemergencyLTwithin72h(ELTgroup)andtheother84weregivenALSSassalvagetreatment.Ofthe84patients,33werefoundtohavereducedMELDscore(,30)onthedayofLT(DGMgroup),51underwentLTwithpersistenthighMELDscore(N−DGMgroup).Themedianwaitingtimeforadonorwas10forDGMgroupand9.5daysforN−DGMgroup.InN−DGMgroupthereisasignificantlyhigheroverallmortality(43.130 was effective i