Objective To study the sensitivity and specificity of ultrasound parameters for diagnosing girls with different types of precocious puberty, and to explore the value of ultrasound in the diagnosis of girls' precocious puberty. Methods There were 263 girls with precocious puberty, including 146 in the Central Precocious Puberty (CPP) group, 117 in the Peripheral Precocious Puberty (PPP )group, and 146 normal girls from February 2016 to February 2018.The uterus, ovaries, and mammary glands were detected.Ultrasonic multi-parameter measurement data were compared to observe the differences and features of ultrasound parameters among children with different types of precocious puberty and their children with normal girls. Results Cervical thickness was the best diagnostic indicator for diagnosing CPP,the critical value was 0.75 cm, the highest specificity index was the thickness of the mammary gland with a critical value of 1.03 cm, and the combination of the two had a diagnostic sensitivity of 92.1% and a specificity of 96.3%.The length of the cervix was the best diagnostic indicator of PPP, the critical value was 1.51 cm, the highest specificity index was the volume of the uterine body, the critical value was 2.87 cm³, and the combination of the two had a diagnostic sensitivity of 90.1% and a specificity of 95.4%.Ovarian volume was the best diagnostic indicator to distinguish between CPP and PPP,the critical value was 2.25 cm³, the highest specificity index was the breast gland length, the critical value was 3.67 cm,and the combination of the two had a diagnostic sensitivity of 93.5% and a specificity of 89.2%. Conclusion Ultrasound examination is non-invasive and reliable, and its ultrasound measurement parameters have high application value in the clinical diagnosis and identification of girls' precocious puberty.