The invention discloses a marine LNG fuel tank and a mounting method thereof. The marine LNG fuel tank comprises a fuel tank body and a buffer mounting component arranged on a ship deck, a connecting column is arranged at the lower end of the fuel tank body, and a piston body is arranged on the connecting column; the buffer mounting part comprises a positioning buffer cylinder corresponding to the connecting column, a piston cavity is formed in the positioning buffer cylinder, a speed adjusting mechanism is arranged at the bottom of the piston cavity, and a liquid passing annular space is formed between the speed adjusting mechanism and the inner wall of the piston cavity; a liquid discharge hole is formed in the positioning ring punching cylinder; a liquid medium is filled in the piston cavity; in the process of hoisting the fuel tank, the connecting column is inserted into the positioning buffer cylinder and moves downwards to a lower limit; when the connecting column moves downwards, the liquid medium in the piston cavity sequentially passes through the liquid passing annular space and the liquid discharging hole and then is discharged outwards. In the process of hoisting the LNG fuel tank, the fuel tank body can stably and slowly land, and the impact on the fuel tank body is reduced, so that the fuel tank body is effectively prevented from being damaged or the occurrence of safety accidents is effectively avoided.

本发明公开了一种船用LNG燃料罐及其安装方法，包括燃料罐体、设置在船舶甲板上的缓冲安装部件，燃料罐体的下端设有连接柱，连接柱上设有活塞体；缓冲安装部件包括与连接柱相对应的定位缓冲筒，定位缓冲筒中设有活塞腔，活塞腔的底部设有速度调节机构，速度调节机构与活塞腔的内壁之间形成过液环隙；定位环冲筒上设有排液孔；活塞腔中装有液体介质；在吊装燃料罐的过程中，连接柱插入定位缓冲筒中并向下移动至下限位；连接柱向下移动时，活塞腔中的液体介质依次通过过液环隙和排液孔后向外排出。发明在对LNG燃料罐进行吊装的过程中，能够实现燃料罐体平稳且缓和地着落，降低了对燃料罐体的冲击，从而有效避免了燃料罐体的损坏或安全事故的发生。