The invention provides a gas supply gas rail of an LNG- diesel oil dual-fuel engine for a ship. The gas supply gas rail mainly comprises a pressure stabilizing cavity 1, an upper mounting plate 2, an injection valve 3, a lower mounting plate 4 and an injection valve small gas rail body 5. The gas supply gas rail is made of a stainless steel pipe, before natural gas enters a gas inlet channel of the engine, an absolutely-airtight pressure stabilizing space is formed, and therefore the natural gas can have stable pressure before being injected through the injection valve; meanwhile the bottom of the steel pipe is provided with the upper mounting plate, the lower mounting plate and the injection valve small gas rail body, the mounting, fixing and injection requirements of the injection valve are guaranteed, intake of the natural gas can be completed just by mounting a corresponding gas injection pipe at a connector of the small gas rail body, and therefore the safe and stable using effect meeting the gas intake requirements of the engine are achieved. It is tested by actual tests that the gas rail can achieve the actual application effect and can be applied to the field of power technology transformation of the LNG-diesel oil dual-fuel engine for the ship.