The invention relates to a design method of a self-adaptive flow distribution adjusting device, which belongs to the technical field of flow control and comprises the following steps: firstly, determining the airfoil profile, the size and the position of an airfoil according to the change relationship of required flow of an outer flow channel and an inner flow channel along with working conditions; then, in combination with theoretical calculation and CFD simulation, determining airfoil attack angle state of each working condition, so that the actual flow of the outer flow channel and the inner flow channel under the corresponding working condition is not smaller than the required flow; and finally, performing stress analysis on the airfoils, and arranging double torsional springs betweenthe adjacent airfoils according to an analysis result, so that the airfoils under the attack angles corresponding to all the working conditions are in a moment balance state. According to the design method of the self-adaptive flow distribution adjusting device provided by the invention, self-adaptive adjustment can be conducted on the flow of different partitions of a fluid channel, it is guaranteed that the flow of fluid in the outer flow channel and the inner flow channel separated by the self-adaptive flow distribution adjusting device meets the flow requirements of the partitions under all working conditions, extra control is not needed in the actual operation process, the operation strategy is simple, and the influence of gravity is avoided.