The invention provides a method, system and device for controlling power consumption of a power amplifier of a microwave communication transmitter, wherein an instruction requiring power size switching or mode modulation is acquired; a linear requirement proposed by a target signal to the power amplifier is computed; and according to a difference between a linear requirement proposed by a current signal to the power amplifier and the linear requirement proposed by the target signal to the power amplifier, the power size switching or the mode modulation can be controlled, and a bias voltage of the power amplifier can be controlled and adjusted. Hence, a bias current can be changed till the linear requirement proposed by the target signal to the power amplifier is satisfied; intelligent control of the power consumption of the power amplifier of the microwave communication transmitter can be implemented; energy waste can be reduced; and a service life of the microwave communication transmitter can be prolonged.