Abstract: During mooring at open wharfs,ships are greatly affected by the offshore environment such as wind,wave and currents,The forces on ships are more complex and the risk of breaking of mooring lines is relatively greater than those of berthing at sheltered wharfs,Taking the 50 000 DWT ship berth in Zhoushan Free Trade Zone as an example,and based on the hydrological and meteorological conditions of the dock water area,mooring stability tests were conducted by using the ship maneuvering simulator,The results show that for a 50.000-ton container ship,when the swell height does not exceed 0.5 m,the wind does not exceed force 8 Beaufort with 9 Beaufort gust in all directions;when the swell exceeds 1.0 m,the wind does not exceed force 7 Beaufort with 8 beaufort gust in N～NE,and force 8 beaufort with 9 beaufort gust in other directions.