Objective: To investigate the ultrasound findings of different types of anterior talofibular ligament injuries and the thickness changes of the healthy side and the diseased side after injury. Methods: The clinical data of 152 patients with suspected unilateral lateral ankle collateral ligament injury were selected for retrospective analysis, and the selection time was from May 2018 to June 2020; MRI examination results were used as the standard, that is, the gold standard diagnosis was diagnosed as anterior talofibular A total of 82 cases of ligament injury (47 cases of grade Ⅰ, 24 cases of grade Ⅱ, 11 cases of grade Ⅲ); all underwent ultrasound examination to compare the positive predictive value and negative predictive value; observe the imaging performance and anterior talofibular ligament after high-frequency ultrasound The detection rate of different types of injury; evaluate the thickness of the uninfected and affected anterior talofibular ligament in patients with anterior talofibular ligament injury; analyze the correlation between the thickness of the diseased side ligament and the type of ligament injury; evaluate the ultrasound diagnosis of anterior talofibular ligament injury AUC value, sensitivity, specificity and Youden index. Results: After high-frequency ultrasound examination of 152 patients with suspected lateral ankle collateral ligament injury, the positive predictive value was 92.86% and the negative predictive value was 94.11%. Compared with the gold standard, the difference was not statistically significant (P>0.05); In addition, 45 cases of type I injury were detected with a percentage of 29.61%, 22 cases of type II injury with a percentage of 14.47%, and 11 cases of type III injury with a percentage of 7.24%. Compared with the gold standard, the difference was not statistically significant ( P>0.05). The thickness of the contralateral ligament is (2.01±0.41) mm, and the thickness of the diseased side ligament is (2.72±0.93) mm; the thickness of the diseased side ligament is higher than that of the contralateral ligament, and the difference is statistically significant (P>0.05); Type I diseased side The thickness of the ligament is (2.54±0.81), the thickness of the type II side ligament is (2.89±1.02), and the thickness of the type III side ligament is (3.11±1.09) mm. Spearman correlation analysis showed that the thickness of the diseased side ligament was positively correlated with the type of ligament injury (r=0.314, P<0.05). ROC curve analysis showed that the AUC value of ultrasonic diagnosis of anterior talofibular ligament injury was 0.933, the sensitivity was 95.10%, and the specificity was 91.40%. Conclusion: High-frequency ultrasound has high clinical value in the injury of the lateral collateral ligament of the ankle, and the thickness of the ligament after the injury of the anterior talofibular ligament is significantly increased than that of the healthy side, and its thickness can increase with the classification of the anterior talofibular ligament injury. And then it rises.