In this article the vibration analysis of a viscoelastic cantilever beam with piezoelectric layers under aeroelastic force and base excitation is investigated. The beam viscoelastic material is assumed to obey the Kelvin-Voight model. Also the piezoelectric layers are located at the top and bottom beam surfaces with series connections. The aeroelastic force based on piston theory is considered to act as an external force on the beam and also the base excitation is assumed to be random. In this research the cantilever beam with two piezoelectric layers are considered as a mechanism to harvest the bending vibration energy. First, the Galerkin method is used to convert the governing partial differential equation into a set of ordinary differential equations. Then the resulted nonlinear ordinary differential equation coupled with electrical circuit equation of piezoelectric layer are solved numerically by Rung-Kutta method. Finally, by analyzing the response of the governing equations, the influence of the system parameters on the vibration behavior of beam and output voltage are discussed. Results show that the increase of fluid velocity increases vibrational energy system which leads to increase of both vibration amplitude and output voltage. In addition, it was shown that structural damping has a significant impact on the output voltage.