A dynamic model of marine LNG supply system was established using Aspen HYSYS,and the relevant working conditions of fuel gas supply system(FGSS) under the maximum gas supply(225 kg/h)were simulated by this model,and various control logic model for maintaining the stability of the system under the change of the inspiratory volume of the main engine was studied. In the maximum working condition,the gas supply pressure of the main engine can be stabilized at 0.7 MPa,and the gas supply temperature was 34.45 ℃. When the intake volume of the main engine was reduced from 225 kg/h to 20 kg/h,if the pump frequency control was adopted and the return valve was maintained unchanged,the pump speed was reduced to 72.83%,the gas supply temperature was 34.78 ℃,the maximum pressure of the buffer tank was 707.7 kPa,and the maximum pressure fluctuation was 0.16%. When the return valve opening control was adopted and the supply pump speed remained unchanged,the supply gas temperature increased to 34.81 ℃,the maximum pressure of the buffer tank was 711.5 kPa,and the return valve opening increased from 15.27% to 33.00%. The research shows that the system can realize 0-100% frequency conversion adjustment in all working conditions of the gas supply system.