Abstract: Modal adjustment method for similar test model of blade was studied on the basis of the lumped mass method. Firstly, the natural frequency formulas of thin plate with lumped mass distribution were obtained according to the small plate deflection theory assumption. Secondly, the vibration characteristics influence rules of the materials and position of the lumped mass on the thin plate were analyzed using ratio coordinate system. Finally, the application method based on lumped mass was given through a practical example, and the effectiveness and correctness of the adjustment method were verified with finite element method from natural frequency and modal shapes.