Abstract: In view of the engineering structure control under the continued environment disturbance, this paper presents a suboptimal method for placement, number and gains of actuators in output feedback control systems. In the approach, the candidate actuator locations contributing little to the performance functional optimum values are removed successively until structural response and controlling force reach maximum at the same time by adjusting parameter Q and R. This approach is simple and computationally efficient, avoiding the complex gradient and the costly functional calculations. Finally, this method is validated through an example simulating multilayer shear frame.