Under condition of a small amount of measured pressure data，to solve the problem of low structure surface normal velocity reconstruction accuracy and resolution or even reconstruction failure using near field acoustic holography technology，a holographic surface interpolation algorithm based on the acoustic radiation modes that can effectively improve the structure normal velocity reconstruction accuracy and resolution is proposed. Firstly，the acoustic radiation modal vectors of holographic surface are calculated；Then，according to the convergence of pressure acoustic radiation modes，the least square solution or Tikhonov regularization solution of the truncated expansion coefficient of pressure radiation modes is obtained，and the pressure values of the interpolated point can be calculated；Finally，the structure surface normal velocity is reconstructed by the interpolated hologram data. Both the simple supported plate simulation and the speaker experiment show that the proposed method can effectively improve the reconstruction accuracy and resolution of the normal velocity of the structure surface with a small quantity of known pressure values，and the effectiveness of the proposed method is verified. Meanwhile，the feasibility of the method is verified by the speaker experiment.