The invention relates to a model experiment device and method of a floating type drilling storage loading and unloading system. The device is characterized in that a motion control system is connected with an electrohydraulic servo actuator in a ship body motion simulation system; the ship body motion simulation system comprises a lower support frame of which the bottom end is fixed on a ground foundation; the top of the lower support frame is provided with a lower table top; the top of the lower table top is connected with an upper table top through a plurality of linear sleeves and the electrohydraulic servo actuator; a TLD (Tension Leg Deck) model comprises a plurality of pulley blocks fixedly arranged on the upper table top; one end of each steel wire rope wound on each pulley block is suspended on a deck model positioned below the middle part of the upper table top, and the other end of each steel wire rope is connected with a weight-balancing mass block at the outer side of the upper table top; the bottom surface of the deck model is provided with a plurality of tensile springs; the other end of each tensile spring is fixed on the ground foundation; a monitoring system comprises a plurality of sensors and dynamometers on the TLD model; and the output ends of each sensor and each dynamometer are connected with a data analysis and acquisition instrument.