The docking process for float-over installation of the offshore wind turbine is analyzed, and the H-shaped catamaran in both frequency domain and time domain is simulated. The motion RAO of H-shaped barge in different wave directions is obtained in frequency domain simulation. The catenary mooring is used to obtain the line tension of hull under the waves during the docking in time domain simulation. Through calculation and analysis, as the length of the line increases, the mooring tension decreases; as the lengths of the mooring lines are near enough, the mooring tensions are similar. The lengths of mooring lines need to be similar and as long as possible.