If the patient is lying on his right side and then percussion is performed, the turbid sound will move. This phenomenon of movement of the turbid zone due to position change is called “mobile turbidity”. The differential diagnosis of mobile turbid sounds needs to identify the different causes of mobile turbid sounds: 1. Increased portal venous pressure: normal hepatic sinusoidal pressure is very low (0-2 mmHg), but when portal hypertension, the hepatic sinusoidal hydrostatic pressure rises (portal pressure lommHg, which is the basic condition for the formation of abdominal fluid), and a large amount of fluid flows into the Disse space, resulting in excessive production of hepatic lymphatic fluid. Elevated hepatic sinusoidal pressure can also cause activation of intrahepatic pressure receptors, which, through the hepatorenal reflex, reduces renal excretion of sodium and aggravates water and sodium retention. 2. Visceral arterial dilation: In the early stages of cirrhosis, visceral vasodilation maintains the effective blood volume in the normal range by increasing cardiac output and heart rate, etc. The interaction of portal hypertension and visceral vasodilation changes the capillary pressure and permeability of the intestine, which facilitates fluid accumulation in the abdominal cavity. 3.Decrease in plasma colloid osmotic pressure: Patients with cirrhosis have reduced intake, decreased liver reserve function and decreased ability to synthesize albumin, resulting in a decrease in plasma albumin and, in turn, a decrease in plasma colloid osmotic pressure, and a large amount of fluid enters the tissue interstitial space and forms peritoneal fluid. 4, other factors: relative lack of plasma cardiac natriuretic hormone and the body’s reduced sensitivity to it, reduced estrogen inactivation, drainage dysfunction due to increased secretion of antidiuretic hormone and reduced secretion of prostaglandins, resulting in renal vasoconstriction, decreased renal perfusion and redistribution of renal blood flow, are all related to the formation and persistence of peritoneal effusion.