A position maintaining system of an offshore structure is disclosed. According to one embodiment of the present invention, the position maintaining system of an offshore structure maintains a position of an offshore structure operated while floating on sea. The present invention comprises: a pump provided to the offshore structure; a plurality of opening portions disposed on the offshore structure to be communicated with seawater; a suction pipe unit connecting the opening portions and a suction hole of the pump; a discharge pipe unit connecting an outlet of the pump and the opening portions; and a control unit controlling driving of the pump and opening and closing of the opening portions. The present invention sucks seawater from the opening portions or discharges the seawater to maintain the position of the offshore structure.
