Objective@#To study the effect of mean arterial pressure (MAP) level on acute kidney injury (AKI) in patients with septic shock, and to determine the best resuscitation target MAP to prevent the occurrence or progression of sepsis- associated AKI.@*Methods@#The study subjects included 168 adult patients with septic shock (age≥65 years) who were admitted to the Department of Intensive Care Unit (ICU) of the First Hospital of Jilin University from January 2016 to January 2019. The clinical data of all enrolled patients were retrospectively analyzed. The baseline data were compared between the AKI group (n=111) and non-AKI group (n=57). Multivariate logistic regression analysis was used to determine the risk factors of AKI in patients with septic shock.@*Results@#① The first, second, third, and forth quartile of ΔMAP (pre-resuscitation MAP minus post-resuscitation MAP) were -24.3-3.9 mmHg, 4.0-12.3 mmHg, 12.4-19.8 mmHg, and 19.9-43.5 mmHg, respectively. The second to fourth quartile interval wasΔMAP ≥4 mmHg.② There were no significant differences in age, body mass index, sex, pre-resuscitation MAP, MAP at first hour, SOFA score, positive culture ratio, negative culture ratio, hypertension, peripheral vascular disease, cerebrovascular accident, chronic obstructive pulmonary disease, gastrointestinal ulcer, liver cirrhosis, and tumor between the two groups (P>0.05). There were significant differences in post-resuscitation MAP (P=0.01), APACHEⅡ score (P=0.02), diabetes mellitus (P=0.01), fluid balance (P=0.01), and ΔMAP from the second to fourth quartile (P=0.03) between the two groups.③ ΔMAP ≥4 mmHg (OR=0.26, 95%CI: 0.12-0.57, P=0.01), diabetes (OR=6.03, 95%CI: 1.35-44.16, P=0.04), and high APACHE Ⅱ score (OR=0.96, 95%CI: 0.84-0.97, P=0.02) were closely related to the increased incidence of AKI in patients with septic shock. Post-resuscitation MAP and fluid balance had no significant effect on the incidence of AKI in patients with septic shock.@*Conclusions@#ΔMAP ≥4 mmHg, APACHE Ⅱ score and diabetes were independent risk factors for the incidence of AKI in patients with septic shock. The incidence of AKI in septic shock patients with post-resuscitation MAP 4 mmHg or more lower than pre-resuscitation MAP is significantly increased.