Abstract： Objectives To determine the clinical significance of left ventricular ejection fraction(LVEF)in different pathological valve surgery.Methods All 984 consecutive patients with isolated mitral stenosis(MS),653patients with isolated mitral insufficiency(MI),138 patients with isolated aortic stenosis(AS),and 288 patients with aortic insufficiency(AI)from 1993 to 2004 were evaluated.All of them underwent valve replacement or repair,and LVEF was detected preoperatively and postoperatively.Results ①The hospital mortality of patients with preoperative LVEF＜50％ was similar as that of patients with LVEF≥50％ in MS group[3.7％ (4/109)vs 3.4％ (30/875),P ＞ 0.05] and AS group [4.5 ％ (1/22)vs 2.6％ (3/116),P ＞ 0.05].The mortality of patients with preoperative LVEF ＜ 50％ was significantly higher than that of patients with LVEF≥50％ in MI group[12.0％ (10/83)vs 3.3％ (19/570),P＜0.01] and AI group [8.5％(5/59)vs 2.2％ (5/229),P＜0.05].②)In MS group,after treatment,the LVEF of patients with preoperative LVEF ≥ 50％ decreased [(61 ± 9)％ vs (64 ± 7)％,P ＜0.01],and increased in patients with preoperative LVEF ＜ 50％ [(56 ± 11)％ vs (44 ± 6)％,P ＜ 0.01].In MI group,after treatment,the LVEF of patients with preoperative LVEF ≥ 50％ decreased [(58 ± 10)％ vs (64 ±7)％,P ＜ 0.01].In AS group,after treatment,the LVEF of patients with preoperative LVEF ＜ 50％ increased [(57 ± 13)％ vs(43 ±5)％,P ＜0.01],and decreased in patients with preoperative LVEF≥50％ [(60 ± 12)％ vs(66 ± 9)％,P ＜ 0.01].In AI group,after treatment,the LVEF of patients with preoperative LVEF ≥50％ decreased[(57 ± 10)％ vs(62 ± 7)％,P ＜ 0.01].Conclusions LVEF has different influence on hospital mortality in different pathological valve diseases in valve surgery.To MI and AI patients,LVEF is an important risk factor on hospital mortality,but in MS and AS patients,it is not a sensitive index.