Objective To investigate the risk factors of hip osteoarthritis(HOA)after hip arthroscopy in patients with femoro-acetabular impingement(FAI)syndrome,and to reduce and prevent HOA.Methods From September 2018 to Septem-ber 2020,106 patients with FAI underwent hip arthroscopy,including 40 males and 66 females,aged from 20 to 55 years old with an average age of(33.05±10.19)years old.The mechanism of injury included 51 cases for sports injury,36 for traffic ac-cidents,and 19 for blunt object injury.The duration of the disease ranged from 5 to 19 days with an average of(12.02±3.69)days.All patients were followed up for 18 months.Patients were divided into HOA group(23 cases)and non-HOA group(83 cases)according to the occurrence of HOA.Multivariate Logistic regression was used to analyze the risk factors of HOA after hip arthroscopy in FAI patients.Results By univariate analysis,aged from 50 to 70 years old,female,body mass index(BMI)＞30 kg·m-2,physical labor,cam type,postoperative infection,last follow-up hip degree of motion(range of motion,ROM)(flex-ion,abduction,adduction,internal rotation)and T?nnis grade 1 and above of the HOA group were higher than those of the non-HOA group(P＜0.05),and the relative appendicular skeletal muscle index(RASM)was lower than that of non-HOA group(P＜0.05).By multiple Logistic regression analysis,cam type,BMI＞30 kg·m-2,last follow-up hip internal rotation ROM and T?nnis grade 1 were risk factors for HOA after hip arthroscopy in FAI patients(P＜0.05).Conclusion FAI classification,body mass index,hip ROM and T?nnis grade are all related to HOA after hip arthroscopy in FAI patients.Follow-up and intervention should be strengthened in high-risk FAI patients to reduce the occurrence of HOA.