Abstract: Thyroid is the largest endocrine organ of human body, and its endocrine role can not be ignored. Nowadays, due to human lifestyle, diet, environment and other factors, the incidence of thyroid cancer is increasing year by year, and it is becoming more and more common in young adults. Papillary thyroid microcarcinoma(PTMC) is difficult to detect because of its small size, strong concealment and lack of clinical features. Ultrasonic two-dimensional gray-scale image features are of great value in the diagnosis of PTMC. New technologies such as ultrasound elastography, contrast enhanced ultrasound, ultrasound guided fine needle aspiration cytology, and artificial intelligence provide new evidence for the diagnosis of PTMC. This article reviews the research progress in ultrasound diagnosis of PTMC.