Cholecystitis is a common and frequent clinical disease, which is divided into acute cholecystitis and chronic cholecystitis according to the condition; it can be divided into calculus, biliary tract infection, and gallbladder dysfunction according to the etiology. The typical clinical manifestations of acute cholecystitis are pain in the right upper abdomen, fever, and positive peritoneal irritation sign (Murphy’s sign); chronic cholecystitis, due to recurrent inflammation, causes adhesions to the gallbladder wall, cystic wall thickening, and scar fibrosis formation, which eventually leads to gallbladder atrophy and decompensation or loss of function. Cholecystitis is considered when the wall of the gallbladder is gross and thickened on ultrasound imaging, exceeding 3 mm. In acute obstructive cholecystitis, caused by stones, the gallbladder is enlarged, full and high tension; in acute purulent cholecystitis, flocculent echogenic floating in the gallbladder; in acute bacterial cholecystitis, inflammatory exudative edema of the cyst wall, showing the “bilateral sign”; in chronic cholecystitis, the cyst wall is thickened, the gallbladder is atrophied and no obvious bile filling is seen. The diagnosis of cholecystitis needs to be made with caution in patients with simple gross gallbladder wall, especially in patients with normal gallbladder morphology and no abnormal sonographic manifestations in the lumen, which should be considered as normal variants. In patients with cirrhosis, ascites, and hypoproteinemia, thickening of the gallbladder wall is a coexisting manifestation of these diseases and should not be rashly diagnosed as cholecystitis without other evidence.