Objective:To explore the correlation between the semiquantitative score of bone ultrasound and the WOMAC OA index in knee osteoarthritis.Methods:From March 2017 to December 2018, 118 patients with knee osteoarthritis diagnosed and treated in Taizhou Hospital of Traditional Chinese Medicine were selected in the research.The patients' bone erosion, joint effusion, synovium hyperplasia and meniscus were evaluated by ultrasound semiquantitative scoring system.Osteoarthritis index of the patients was investigated at the same time.The correlation between the semiquantitative score of myoskeletal ultrasound and WOMAC OA index in knee osteoarthritis was analyzed.Results:In 118 patients with knee osteoarthritis, the semiquantitative scores of myoskeletal ultrasound of bone erosion was (2.33±0.37)points, joint effusion was (2.05±0.26)points, synovial hyperplasia was (2.24±0.15)points, abnormal meniscus position was (1.67±0.28)points, meniscus shape and signal was (1.15±0.14)points.The WOMAC OA index scores of patients' pain was (29.52±6.68)points, stiffness was (11.43±3.78)points, dysfunction was (93.85±18.73)points, and total score was (134.80±29.19)points.The scores of bone erosion, joint effusion, synovium hyperplasia and meniscus in semiquantitative score of muscle and bone ultrasound were positively correlated with the total score of WOMAC OA index( r=0.435, 0.317, 0.429, 0.294, 0.282, all P<0.05). Conclusion:Semiquantitative score of muscle and bone ultrasound can better reflect the degree of knee joint injury, which is positively correlated with WOMAC OA index.We can use the semiquantitative score of muscle and bone ultrasound and WOMAC OA index to predict the condition of patients with knee osteoarthritis.