Airborne and ship-borne power systems are stand-alone power systems composed of generators and various power electronic converters. The response speed of the generator is much lower than that of the power electronic converter. The rapid load power transient will lead to significant fluctuation of the DC bus voltage, and also may threaten the safe and stable operation of the generator. This paper studies the transient power active suppression method based on the active capacitor converter. Firstly, the active rectifier is used to match the response speed of the generator by limiting the rate of change of the rectifier input power. Then, the disturbance of the load power to the generator is avoided. And an active capacitor converter is used to compensate the instantaneous deviation of the output power and the load power of the rectifier, thereby ensuring the fast response speed of the power system when the load fluctuates rapidly, while avoiding fluctuations in the bus voltage. The architecture and operation principle of the transient load power suppression based on active capacitors are presented, the corresponding control strategy is studied, and the energy management method of energy storage capacitors is analyzed as well. Finally, the feasibility and effectiveness of the presented method is verified with experimental results.