Objective To investigate types of knee joint injury among island garrison force and the effect of arthroscopy,and also to recommend related preventive measures.Methods Forty-two cases of knee joint injury were collected from the medical data registered from March,2012 to April,2013,and diagnosis and treatment were performed by arthroscopy.Results Of the 42 cases of knee joint injury,there were 31 cases of anterior cruciate ligament injury,14 cases of internal meniscus injury combined with external meniscus injury,2 cases of simple meniscus injury,1 case of external discoid cartilage injury,2 cases of chondromalacia patellae,3 cases of traumatic synovitis,1 case of posterior cruciate ligament injury,and 1 case of traumatic knee joint arthritis.Following treatment by arthroscopy,all the patients returned to duty.Conclusion In the knee joint injury that occurred among island garrison military per-sonnel,the highest incidence was anterior cruciate ligament injury,with complete rupture of ligament in most cases.There was a rela-tively high rate of misdiagnosis and treatment delay.For this reason,attention should be paid to knee joint injury occurred among mili-tary personnel,and early arthroscopy should be performed as early as possible,so as to improve cure rate.