The effect of different berth lengths on the mooring of 172,000 m3 LNG ship is studied by the 1:60 overall model test.The movement and cable tension of the ship under the combined action of wind,wave and flow are analyzed.The research shows that under the conditions of transverse wave,transverse wind and falling current,the length of berth is shortened,and the bow and stern cable force shares part of the transverse cable force,which is beneficial to the balanced bow and stern cable and transverse cable force,and the maximum cable forces become smaller;the change of berth length has little effect on mooring force under the conditions of downwave,downwind and falling current;under the condition of oblique wave,transverse wind and falling current,the ship is affected by oblique wave,and the wave force is distributed in both directions,and the force of spring cable is basically the same as that of transverse cable or bow and stern cable;when the wind is following,the spring force will be greater than the transverse force and the bow and stern force.The study recommends a suitable berth length for the Tianjin LNG project,which can provide reference for the design of the wharf.