This paper prescribes a movable voltage-variable & frequency-variable on shore power supply system which successfully provids on shore power for container vessel at port. The high-voltage power supply (10 kV/50 Hz/2 000 kV·A) for the Quay Cranes is used as the power input of the system after frequency and voltage converting (450 V/60 Hz),and then was put out and supplied to vessel. This system is flexible with positive effect on energy-saving and emission reduction. Besides, there is no need of civil reconstruction to container terminals, which is suitable for the busy ports in China.