Objective: To investigate the value of shear wave elastography (SWE) in the detection of early damage to knee cartilage in patients with hemophiliac arthropathy, with the aim of providing a new examination method for early damage to knee cartilage in patients with hemophiliac arthropathy. Methods: Twenty-six male hemophilia A patients with recurrent bleeding in the knee joints and 30 male healthy volunteers matched for age, height and weight who visited our hospital from June 2022 to November 2023 were selected as study subjects. Routine two-dimensional ultrasonography was performed on the knee joints of both groups to obtain the cartilage thickness values of different parts of the knee joints and HEAD-US-C scores; further SWE examination of the knee cartilage was performed to obtain its Young's modulus values and shear wave velocity values. To analyze whether there was a statistical difference between cartilage thickness, Young's modulus value, and shear wave propagation velocity in different parts of the knee joint between the two groups. The patients with mild, moderate and severe hemophilia were stratified to analyze whether the measured parameters were statistically different. To statistically determine whether there was a correlation between HEAD-US-C scores and Young's modulus and shear wave velocity of cartilage in different parts of the knee joint in the case group of patients. Results: (1) The difference in cartilage thickness in different parts of the knee joint between the case group and the control group was statistically significant in a two-by-two comparison (P < 0.05), and the difference in Young's modulus and shear wave propagation velocity of the intercondylar and lateral condylar cartilage in a two-by-two comparison was statistically significant in a two-by-two comparison between the case group and the control group (P < 0.05).(2) There was no statistically significant difference in the thickness of the cartilage in different parts of the knee joint in a two-by-two comparison of the patients in the mild, moderate, and severe case groups (P>0.05). Young's modulus and shear wave propagation velocity of the intercondylar and lateral condylar cartilage of the knee joints of patients with hemophiliac arthropathy were compared among the three groups of mild, moderate, and severe cases, and except for the statistically insignificant difference between the moderate group and the severe group (P>0.05), the differences of the other parameters were statistically significant in a two-by-two comparison among the three groups (P<0.05). (3) There was a negative correlation between Young's modulus of knee cartilage, shear wave velocity and HEAD-US-C score of the patients in the case group, implying that the stiffness of knee cartilage of the patients in the case group decreased with the increase of the score. Conclusion:SWE can quantitatively measure the changes in the stiffness of knee cartilage, and can be more sensitive than conventional ultrasound in detecting early damage to cartilage in patients with hemophiliac arthropathy.