The invention discloses an LNG fuel boat fuel gas dual-wall pipe broken simulation box and a simulation method thereof. The LNG fuel boat fuel gas dual-wall pipe broken simulation box comprises a box body, a sealing plate for sealing the top of the box body, a simulation smoke exhaust pipe, a compression air inlet pipe, a smoke bomb throwing pipe and a pressure meter, the simulation smoke exhaust pipe, the compression air inlet pipe and the smoke bomb throwing pipe are all fixed to the sealing plate and are communicated with the inner cavity of the box body, the pressure meter is fixed to the sealing plate through a welding base, and a root valve is fixed to the welding base of the pressure meter. The simulation box can truly simulate a small-caliber broken leakage state of an LNG fuel boat fuel gas dual-wall pipe, the simulation box and a smoke bomb in the box can be repeatedly utilized, the cost is saved, and the workload of an LNG fuel boat fuel gas dual-pipe-wall broken monitoring experiment is lowered.