Objective To investigate the effect of quantitative ultrasound bone mineral density test on the screening of osteoporosis in patients with knee osteoarthritis and to explore the relationship between knee osteoar-thritis and osteoporosis. Methods 160 patients with knee osteoarthritis were divided into 4 groups:Ⅰ,Ⅱ,ⅢandⅣby Kellgren-Lawrence and measured height,weight,age,quantitative ultrasound bone mineral density and dual energy X-ray bone density.We compared the T values measured by quantitative ultrasound bone mineral density test and dual energy X-ray bone density,assessed the accuracy of quantitative ultrasound bone mineral density test for osteoporosis,and investigated the correlation between the value of quantitative ultrasound bone mineral density and knee osteoarthritis in different grades. Results Quantitative ultrasound bone mineral density was positively correlated with dual energy X-ray bone density(r = 0.751,P < 0.05). The AUC of diagnosis of osteoporosis by quantitative ultrasound bone mineral density test with T<-2.5 was 0.774,95% CI was 0.676 and 0.791,specificity was 96.7%,sensitivity was 85.7% and Youden index was 82.4%.With an increase in the grades of Kellgren-Law-rence,the knee osteoarthritis gradually worsened.The T values of quantitative ultrasound bone mineral density and dual energy X-ray bone density increased gradually in negative direction,and the difference was statistically signifi-cant(P<0.001).Conclusions Quantitative ultrasound bone mineral density test has good specificity and sensi-tivity and can be used to screen patients with knee osteoarthritis. The more severe the knee osteoarthritis is,the easier to develop osteoporosis.