Objective:To analyze the monitoring data of Kashin-Beck disease (KBD) in Gansu Province and learn about the long-term trend of KBD incidence.Methods:The X-ray detection rate of children with KBD in Gansu Province from 1990 to 2021 was collected through Gansu Provincial Center for Disease Control and Prevention. Joinpoint regression model was used to analyze the trend of X-ray detection rate of KBD in children. The annual percent change (APC) and average annual percent change (AAPC) were used to analyze the trend of the observed indicators. In addition, a polynomial regression model was constructed to fit the change of X-ray detection rate of children with KBD over time.Results:From 1990 to 2021, a total of 126 726 children were examined for KBD by X-ray in Gansu Province, with 3 011 positive cases, X-ray detection rate of KBD in children was 0 in 2019 - 2021. Joinpoint regression model analysis showed that the X-ray detection rate of children with KBD in Gansu Province from 1990 to 2018 showed a decreasing trend (AAPC = - 14.40%, P = 0.001). The APC of 1990 - 1998, 2002 - 2008 and 2008 - 2012 was - 17.75%, - 21.89% and - 49.89%, respectively, showing a decreasing trend ( P < 0.05). The APC of 2012 - 2018 was 6.15%, but the trend change was not statistically significant ( P = 0.475). The curve fitting of X-ray detection rate of KBD in children in Gansu Province over time was carried out, and the quadric polynomial equation was y = 0.000 314 5 x4 - 0.021 37 x3 + 0.487 1 x2 - 4.635 x + 22.08. Conclusions:The condition of KBD in children of Gansu Province has been effectively controlled. The X-ray detection rate has remained at a relatively low level since 2012, and it has reached a state of elimination since 2019.