In this paper, we propose a novel method of generating and executing active impact motion on a quadruped robot by mimicking active impact motion of quadruped animals. In order to generate active impact motion postures, we divide the whole active impact process into three phases and present a Center of Gravity (COG) trajectory planning method for these phases. A controller based on virtual model control (VMC) is used for active impact motion execution and a pitch attitude adjustment controller is utilized to stabilize the robot. Besides, a Hopf oscillator-based Central Pattern Generator (CPG) network with controllable locomotion stride is responsible for generating control signals of quadruped gaits during active impact motion. In order to verify effectiveness of the proposed control strategy, we show experimental results that a quadruped robot pushes the target object weighing 15 kg away for 50 cm by executing active impact motion.