(Disclaimer: This article is for scientific use only, and the information in the following content has been processed to protect patient privacy) Abstract: Chondroblastoma is a rare benign tumor that is more common in adolescents. It cannot be prevented, and surgical excision is the main method, and it is not easy to recur after surgery. Early consultation at the onset of suspected symptoms can improve the outcome of treatment. In this case, a 16-year-old male patient with pain and swelling in the right knee joint 2 months ago, whose symptoms were relieved after rest or oral medication, was diagnosed with chondroblastoma by combining medical history as well as examination, and the symptoms were significantly relieved by surgical treatment. The patient was diagnosed with chondroblastoma two months ago. He complained of pain and swelling in his right knee joint 2 months ago, but due to his busy school schedule, he tolerated the pain until the end of his exams, and the pain was relieved by rest or oral pain medication when he moved and walked the knee joint. After the initial consultation, the patient was given a detailed examination. The patient’s knee joint was obviously swollen, but there was no deformity, the local skin color was normal, the skin temperature was normal, and there was pain on pressure on the knee joint. And the knee joint was persistently painful and swollen. The first consideration was to suspect a bone lesion and the patient was advised to take an X-ray of the knee joint, and it was obvious from the film that the lesion area was located in the epiphysis and tended to spread across the growing cartilage toward the epiphysis, and the imaging diagnosis suggested a high tendency to chondroblastoma. Second, the treatment process However, the diagnosis could not be fully confirmed by the above examinations, and the patient was suggested to undergo surgery to clarify the diagnosis through postoperative pathological laboratory tests, because pathology is the gold standard for a clear diagnosis. After communicating with the patient and his family, the patient underwent surgical treatment by scraping and bone grafting + internal fixation of the lesion. After the surgery, the patient’s knee pain and swelling were significantly relieved, and the stitches were removed after 2 weeks. The patient was discharged from the hospital smoothly, and was advised to review regularly in the outpatient clinic after discharge, and to walk with crutches within 6 weeks after surgery, and to walk with weight on crutches basically at 3 months after surgery, and there was no local discomfort in the knee joint. At 6 months after surgery, the crutches can be completely abandoned. About 1 year after surgery, after the bone is completely healed, the internal fixation can be removed. Chondroblastoma is ineffective in conservative treatment and should be removed surgically as soon as it is detected. In this patient, the tumor is located in the bone growth area of femur, and a part of the growth plate will be attached when it is removed. After surgery, it may affect the development of lower limbs and lead to unequal length of lower limbs. Therefore, we need to pay attention to the height and postural changes of the patient during postoperative review. In addition, although chondroblastoma is a benign tumor, it is prone to malignant transformation into chondrosarcoma once it recurs. Therefore, close observation and regular review for about 3 years after surgical removal is needed to prevent recurrence. We are glad that the lesion is completely cleared after the treatment, but in terms of daily life, we suggest the following to the patient: 1, diet, the patient should strengthen nutrition after the surgery, you can eat high protein, high vitamin, easy to digest food. The nutrition should be balanced, and spicy, stimulating and smoked foods should be avoided. 2. Chondroblastoma is a benign tumor derived from chondroblastoma cells, which should be removed by surgery as soon as possible and can be cured by timely treatment. Apart from chondroblastoma, many bone tumors occur in adolescents because this is the most active period of bone growth and development, and if bone cells mutate during this period, they will be transformed into tumor cells. Therefore, if adolescents have unexplained limb swelling, pain, deformity and other abnormalities, they must pay high attention and seek timely medical consultation, and review regularly after treatment.