In order to study the safety and operability of the two-ship dismantling method of the offshore platform in complex sea environment, a method combining hydrodynamic numerical calculation and tank model test is used. Based on the comparison between the two-ship hydrodynamic coupling calculation and water tank model test, the variation of the hydrodynamic performance and the amplitude of the motion response of the barges are analyzed under the ideal sea condition and the regular wave action close to the actual condition. The design of Deck Mating Unit (DMU) is improved. Through the comparison of the experimental data and numerical calculation data, the conclusion that the stress is in a reasonable range is gotten. Some guidance for the rationality of the actual construction is put forward.