Fuel flow control method and fuel flow control system of gas turbine combustor for humid air gas turbine

Provided is a fuel flow control method of a gas turbine combustor 2 provided in a humid air gas turbine, by which method NOx generation in the gas turbine combustor 2 is restricted before and after the starting of humidification and combustion stability is made excellent. The fuel flow control method of a gas turbine combustor 2 provided with a plurality of combustion sections, to which a fuel is individually supplied, a part of the gas turbine combustor 2 comprising a combustion section or sections, which are more excellent in flame holding performance than the remaining part, the method comprising evaluating a moisture content of a combustion air at the startup of humidification on the basis of a humidification water quantity and an air temperature after humidification and controlling a fuel ratio supplied to the combustion section or sections of excellent flame holding performance when fuel ratios of fuels supplied to the respective combustion sections are controlled in accordance with a humidified state of a compressed air brought about by a humidifier 4 provided in the humid air gas turbine.