Inertial actuators are usually used in active vibration control of helicopter, additional weight of which generally has to account for 4%-5% of fuselage weight to achieve satisfactory control effect. This paper proposes the use of light-weight piezoelectric stack actuators (PSA) for active vibration control of helicopter to reduce additional weight, and presentes a coupled fuselage/piezoelectric stack actuator optimization method. By using the sub-structure method based on frequency response functions, the coupled helicopter fuselage structure/piezoelectric stack actuator frequency domain equations are established. Setting the minimization of controlled acceleration responses as the objective, the installation locations of piezoelectric stack actuators and controller parameter optimization are investigated. Real-coded genetic algorithms are used to simultaneously optimize the variables of discrete locations and continuous control weighting parameters so as to obtain the most effective vibration suppression in the constrained range of control voltages. Numerical analysis and control simulation in the time domain for an elastic line model of a helicopter fuselage are performed. The results indicate that the method presented in this paper can effectively find the optimal parameters of vibration control and achieve significant effect of vibration suppression.