An ultra-wideband low-noise amplifier circuit with low power consumption includes a cascode amplifier circuit module and an output combining circuit module. The cascode amplifier circuit module receives an input signal, and outputs a first output signal and a second output signal. The output combining circuit module receives the first output signal and the second output signal, and applies respective phase shifts to the first output signal and the second output signal for reducing a phase difference between the first output signal and the second output signal, so as to obtain a combined output signal.