Abstract: Objective To discuss the best opportunity of using continuous renal replacement therapy (CRRT) for the treatment of infective acute kidney injury,and provide certain clinical data for standard treatment in patients with acute kidney injury. Methods From January,2013 to December,2015,120 patients with acute kidney injury having CRRT treatment in our hospital were chosen and divided intoⅠ,Ⅱ and Ⅲ period group by KDIGO criteria.The hospital mortality and renal function recovery rate were compared among the three groups.The APACHE Ⅱ score,SOFA score,oxygenation index,mean arterial pressure,levels of serum creatinine and blood urea nitrogen,cases using vascular active drug were compared before and 48 h after CRRT treatment in each group. Results The mortality and renal function complete recovery rate among the three groups had statistically significant differences (χ²=10.394 and 22.200,all P<0.05).The mortality rate in phase Ⅲ group was significantly higher than that in phase Ⅰ and phase Ⅱ group,while the renal function fully recover rate in phase Ⅲ group was significantly lower than that in phase I and phase Ⅱ group,the differences was statistically significant (χ² ≥ 6.545,all P<0.017).The serum creatinine,blood urea nitrogen,oxygenation index,mean arterial pressure,APACHE Ⅱ score and SOFA score in phase Ⅰ and phase Ⅱ groups were improved significantly after the treatment (t ≥ 4.09,all P<0.05),but not in phase Ⅲ group (t ≤ 1.61,all P>0.05). Conclusion CRRT treatment can obviously improve the prognosis of period Ⅰ and Ⅱ patients,but not of period Ⅲ patients (KDIGO standard),the best opportunity for CRRT should be paid more attention in practice.