In order to study vibration characteristics of an active hydraulic excitation system, a vibration control testing system of elastic plate based on pipeline network was designed. The vibration testing was carried out for elastic plate by using a three axis acceleration transducer and a signal acqusition card. Vibration signal was preprocessed by five-point slippage moving average method, and Fast Fourier Transform (FFT) was carried out. By using the iterative method for least squares, numerical fitting and frequency domain identification were proceeded out for experimental modal parameter of vibration response in space direction of the elastic plate. So, it provides theoretical basis on how to determine the optimal vibration frequency of the vibrating screen.