Command shaping is a convenient feedforward control method, which has been widely used in industry. Due to the uncertainty of the system model and the unavoidable interference, the current research focus of command shaping is to improve the robustness of the method, which leads to the increase of the conservatism of the system and the complexity of the parameter tuning of the shaper. In this paper, an improved VI shaping method, which consists of four pulses, is proposed based on the idea of the two-mode ZV shaping method and EI shaping method. In the design process, two virtual frequencies are selected on both sides of the natural frequency, which are adjusted according to the oscillation tolerance limit to determine the amplitude and the action time of the pulse. Compared with the traditional instruction shaping method, this shaping method has stronger robustness and higher level of oscillation suppression, and the convenience of parameter setting has been greatly improved. Combined with the improved command shaping method proposed in this paper, a control structure combining command shaper and double closed-loop control is proposed for the quadrotor slung system. The stability of closed-loop command shaping control structure is analyzed using the root locus method. Simulation verifies the effectiveness of this method, and compared with other shaping methods, it also shows its superiority.