Presently the electric power harvested from vibration energy by existing researches is mostly at the level of μW or mW, which is not available for structural vibration energy harvesting due to the characteristics of lower frequency, bigger mass, and higher Vibration Energy. Therefore, a novel vibration energy harvesting method via pulse liquid flow for structural vibration is put forward. The principle of the method is mainly depicted as follows: the pulse liquid flow motivated by external vibration twirls the hydraulic motor’s output shaft; then electric power is produced by the generator rotor due to the shaft torque. In this paper, the Energy Harvesting Model has been built with the help of the fluid mechanics principle and the electromagnetic induction principle. In addition, the formula for output voltage was derived and, meanwhile, the influence of the piston’s moving speed amplitude on output voltage has been analyzed as well. Ultimately, we have designed an experimental setup in order to verify the rationality of the analytical method. In our experiments, sinusoidal mechanical excitation was used to test the Energy Harvesting characteristics by the J95-I absorber testing platform. According to the results, the waveform of output line voltage is in a good agreement with the theoretical analysis, which shows effectiveness of this novel method and the worth of which to help solve the problem of dependable power supply for current semi-active vibration control systems.