B-mode ultrasound is an emerging discipline, which has developed rapidly in recent years and has become an indispensable diagnostic method in modern clinical medicine. Ultrasound diagnosis originated in the 40’s. In the early 50’s, A-type ultrasound diagnostic method was applied to clinical practice, and soon B-type, M-type and D-type ultrasound were introduced, and in the 70’s, B-type rapid imaging technology emerged, and in the early 80’s, pulsed and color D-type ultrasound was successfully developed. Nowadays, the success of color imaging has made the sonograms of heart, arteries and veins, lymphatics and bile ducts more realistic and clear at a glance. In recent years, interventional ultrasound has gradually become popular, and the application of body cavity probes and intraoperative probes has expanded the diagnostic range and improved the diagnosis and treatment level. Ultrasound is painless, non-invasive, non-radioactive and reusable for the patient, which is very popular among doctors and patients. In clinical applications, ultrasound can clearly display various cross-sectional images of organs and surrounding organs, and because the images are rich in solidity and close to the real structure of anatomy, ultrasound can be used to make early and clear diagnosis. For example, when diagnosing non-metallic foreign bodies in ophthalmology, it can show retinal and retrobulbar lesions in the case of vitreous opacities. It is specific for non-invasive detection of congenital heart disease, rheumatic heart disease, and mucus disease in the heart, and can replace most cardiac catheterization. It can also be used for the determination of the throughput, direction and velocity of blood flow in small vessels can be widely used. Early detection of hepatic occupying lesions has reached the level of 1 cm. Ultrasound can also clearly show the common bile duct of the gallbladder, hepatic duct, extrahepatic bile duct, pancreas, adrenal gland, prostate, etc. Ultrasound can detect any occupying lesions, especially for the physical characterization of fluid and cysts, as well as their quantity and volume. The detection rate of stones in various ducts is higher than that of traditional examination methods. For obstetrics, it has solved many difficult problems that were difficult to detect in the past. For example, it is possible to locate the placenta, measure amniotic fluid, and make early diagnosis of singleton and multiple fetuses, fetal development, and whether there are abnormalities and gravidity. However, ultrasound also has its limitations that are difficult to overcome at present. First of all, its penetrating power is weak, and it is difficult to reach the deep parts of bones and air, so it is difficult to detect air-containing organs, such as lungs and gastrointestines, and the diagnosis of adult cranium is inferior to that of X-ray and CT. With current instruments, it is not easy to detect tumor tissues around 1 cm, so ultrasonography is negative; it does not exclude the existence of tumor lesions around 1 cm. Secondly, due to the occurrence of multiple repeated reflexes in the reflex method and the phenomenon of pseudo-reflexes due to the interference of collateral discrimination, it is sometimes easy to cause misdiagnosis.