To investigate the role of acute kidney injury staging in multiple organ dysfunction syndrome (MODS) patients with acute kidney injury (AKI) for deciding the opportune time of continuous blood purification (CBP). A retrospective study was conducted. One hundred and twenty-six MODS patients with AKI in general intensive care unit (ICU) and emergency intensive care unit (EICU) requiring continuous venous-venous hemofiltration treatment were enrolled. According to the criteria of "Kidney Disease: Improving Global Outcomes Organization (KDIGO standard)" and acute physiology and chronic health evaluation II (APACHEII) score, the patients were stratified into KDIGO 1, 2, 3 groups and APACHEII score of <15, 15-25, >25 groups. ICU survival rate and renal function outcome, CBP treatment total ultrafiltration, average ICU day and the average medical costs of survivals were compared among groups. Compared with APACHEII ≤ 25, KDIGO 1, 2 hospitalized patients had significantly higher survival rate [94.1% (32/34) vs. 76.8% (43/56), P<0.05]. Renal function improvement rate in survivors of KDIGO 1, 2 patients was significantly higher than that in APACHEII ≤ 25 [90.6% (29/32) vs. 62.8 (27/43), P<0.01], and number of patients requiring CBP treatment, mean ICU day, and medical expenses were significantly reduced (CBP treatment of total ultrafiltration: 199.0±44.7 L vs. 239.0 ± 73.3 L, the mean length of stay in ICU: 12.9±3.4 days vs. 15.1±4.8 days, medical expenses: 2.6±0.4 million vs. 3.0±1.0 million, all P<0.05). There was no significant difference in above indexes between survivors in KDIGO 3 and APACHEII>25, and the indexes in KDIGO 3 and APACHEII >25 were worse than those in KDIGD 1, 2 and APACHEII>25. In patients of MODS accompanied by AKI, compared using as APACHEIIscore≤25 as opportune time to start CBP, to commence the treatment in the period of KDIGO standard 1, 2 cannot only improve patient survival with recovery of renal function, but also can reduce the ICU stay and medical expenses.