Abstract: Kidney is the organ with the most abundant blood supply. It has a strong ability of selfregulation of blood flow, which makes the blood flow of kidney relatively stable when the arterial pressure changes in a certain range.Various causes, which range from inflammation, sepsis, insufficient capacity,  obstruction to ischemiareperfusion injury and surgery, can lead to impaired autonomic regulation of renal blood flow.  At this time, small fluctuation of arterial blood pressure may lead to obvious fluctuation of glomerular filtration rate, contributing to acute renal function damage.Therefore, the monitoring of renal perfusion is of significant importance.Renal perfusion can be monitored by renal ultrasound such as color  Doppler, renal blood flow spectrum,  contrastenhanced ultrasound，and tissue oxygen monitoring such as near infrared spectroscopy, magnetic resonance imaging tissue oxygen monitoring in clinic.Due to various potential diseases and basic disease status, the optimal blood pressure for each patient is different to ensure adequate renal perfusion pressure.Clinical practice prefers lower central venous pressure,  and the titration and individualized therapy strategies guided by renal blood flow perfusion to regulate body volume status and renal perfusion pressure.

Key words: acute kidney injury, hemoperfusion, renal circulation , ultrasonography, vascular resistance