Abstract: Objective To investigate the value of ultrasonography in the diagnosis of exercise-induced muscle injury and summary characteristics of ultrasound image for the diagnosis of muscle injury caused by exercise. Methods From February 2015 to February 2017, 112 cases of suspected exercise-induced muscle injury patients in our hospital were selected as the research objects. The ultrasonography was performed in all patients, and the final diagnosis was also combined with medical history, clinical manifestations, and biopsy by local tissue biopsy if necessary. With the final diagnosis as the standard, the accuracy rate of muscle injury detected by ultrasound was investigated, and the imaging features of muscle injury under ultrasound were discussed. Results A total of 112 cases were diagnosed as lower extremity muscle injury without tendon injury and myometrial injury, including 87 cases of gastrocnemius injury and 25 cases of extensor injury. The accuracy of ultrasound diagnosis was 91.96%, and the misdiagnosis rate was 8.04%. The diagnostic accuracy of ultrasound for simple muscle contusion, simple intramuscular hematoma, partial muscle rupture with hematoma and complete muscle rupture with hematoma were 91.11% (41/45), 92.68% (38/41), 93.33% (14/15) and 90.90% (10/11), respectively. Ultrasound imaging features of muscle injury include: for simple muscle contusion, there was mainly muscle swelling, increased thickness, and blurred pinnate enhanced echo; for muscle partial rupture combined with hematoma, there was mainly muscle partial rupture, and no echo hematoma around it; for the complete muscle rupture and hematoma, there were muscle continuity destruction, disruption and anechoic hematoma. Conclusion Ultrasound diagnosis of muscular injury caused by exercise has high accuracy. It is easy to operate, quickly to get results, and repeatable. It can be used as the first choice for clinical diagnosis of muscular injury caused by exercise.