In view of long time-consuming problem of rechecking the bending radius of the channel after optimizting and adjusting the navigation mark,based on the characteristics of the channel maintenance site,a quick estimation method for the bending radius of the channel marking is proposed.The method is obtained based on the connecting line of the adjacent navigation mark action distance,the circumscribed arc,the navigation width,the trigonometric function equation,and the coordinate system theory.Through the derivation of the sine and cosine theorems,the radius of the circumscribed circle of the navigation mark connecting line can be solved.Based on the coordinate system,the radius of the circumscribed circle of the navigation mark connecting line with obstruction can be calculated by using the triangular analysis.The verification of the setting mark in three typical curved river sections has verified the correctness and timeliness of the rapid estimation of the channel bending radius.The results can provide reference for how to quickly estimate the bending radius on site,so as to accurately and timely check the bending radius of the channel.