The invention discloses a dead ship hydrodynamic power generation device and method, and the device comprises generators which are located at the two sides of a ship; a ship side road door opening andclosing device which is used for opening / closing a ship side road door; a generator telescoping mechanism which enables the generators to extend out of a cabin and retract into the cabin; a control circuit which is used for controlling forward rotation or reverse rotation of each motor of a main circuit to realize opening and closing of the road door and stretching of the generator. When the shipstops, the generators extend out of the cabin; and when the ship sails normally, the generators retracts into the cabin. Kinetic energy, generated by impact of water flow on the ship when the ship isparked, is used for pushing paddles on the generators to rotate, and the energy generated by water flowing is converted into electric energy; when the ship sails, the generators are retracted into the ship body, and as long as the relative speed between the ship and water exists, the electric energy can be provided for the ship, so that the generating capacity of the ship generator set can be reduced, the fuel consumption is reduced, the energy is saved, the emission is reduced, and the device is particularly suitable for inland ships.