The embodiment of the invention provides an asymmetric tail-shaped hydrofoil hydraulic damping identification method. The method comprises the steps that a vibration response is generated, and the frequency component of the vibration response is obtained; interference is eliminated, and a new vibration response after filtering is obtained; the maximum value and the minimum value of the new vibration response are located, and vibration response equilibrium points are obtained; all the vibration response equilibrium points are fit, and displacement of the discrete points corresponding to a fitting curve is obtained; the vibration response after calibration is obtained by making the displacement of the discrete points subtracted from the vibration response between the equilibrium points; themaximum value and the minimum value of the vibration response after calibration are located again; by adopting a logarithmic decrement method, hydraulic damping ratios are obtained based on an upper extreme point and a lower extreme point; when the relative error of the upper hydraulic damping ratio and the lower hydraulic damping ratio is less than 0.5%, the average value of the two ratios is thefinal value, otherwise, step 5 is executed again for conducting iterative correction. According to the method, the identification accuracy of hydraulic damping characteristics of the blade structureunder complex unsteady hydraulic excitation conditions is greatly improved, and then the underwater structure flow-induced vibration amplitude and fatigue life prediction accuracy is improved.