The utility model relates to a two gas supply system of marine CNG and control system, two gas supply system are including the gas cylinder group and two gas supply system casees that are connected, be equipped with gas supply line A and the gas supply line B who is connected in two gas supply system incasement portions, install the root valve A of system, high pressure isolating valve A, overcurrent protection valve A, high -pressure filter A, high -pressure relief pressure valve A, gas supply valve A on gas supply line A, gas supply line A's a period number is outside in two gas supply system casees, installs manometer A or pressure sensor A, natural gas gas engine A in this section, the beneficial effects of the utility model are that: two sets of gas supply system are two single fuel host computer air feed respectively, and to the boats and ships of single fuel list host computer, two sets of gas supply system connect a single fuel host computer jointly, one of them cover work, and other one set is standby system. Gas supply system changes the high -pressure natural gas in the CNG gas cylinder into satisfy natural gas engine air feed demand the low pressure natural gas.