Ultrasound is divided into strong echo, high echo, isoechoic, hypoechoic, weak echo, and no echo according to the different gray scale levels. Generally hyperechoic similar to the echo of renal cortex is hypoechoic, in ultrasound performance benign lesions can show hypoechoic, malignant lesions can also show hypoechoic; on the basis of fatty liver, hemangioma can show hypoechoic solid mass, metastatic hepatocellular carcinoma can show hypoechoic solid mass, primary hepatocellular carcinoma can also show hypoechoic solid mass, hepatic abscess can show hypoechoic solid mass, the Uneven fatty liver can present as hypoechoic areas. To determine whether the hypoechoic mass is benign or malignant, it is necessary to combine with other ultrasound features to make a comprehensive judgment, and sometimes it is necessary to do enhanced CT, enhanced MRI, ultrasonography to determine the benign or malignant nature, or to do puncture biopsy to determine the benign or malignant nature.