Abstract: Disclosed is a fuel mixed injection method for a gas turbine. The method includes the following steps: arranging a secondary fuel injection nozzle and a secondary air injection nozzle on a secondary combustion section, wherein the secondary fuel injection nozzles is closer to a main combustion section than the secondary air injection nozzle; and injecting secondary fuel and secondary primary air in sequence through the secondary fuel injection nozzle and the secondary air injection nozzle, respectively, thus enabling the secondary fuel to spontaneously combust in a mainstream high-temperature flue gas atmosphere to form a transverse jet flame and increase the flame lift-off height.