The invention discloses a frequency-agile and low-power consumption frequency source. The frequency source produces multiple signals through a frequency multiplier circuit, wherein one of signals is used as a DDS reference signal by a DDS, and other signals provide a local oscillation signal required by frequency mixing; a DDS circuit outputs small-step intermediate frequency signal after receiving the reference signal, a switch filter circuit selects the corresponding frequency through a switch after receiving the local oscillation signal, thereby realizing the frequency-agile hopping of thefrequency; the switch filter circuit adopts a combination of a Gallium-Arsenide switch and a power controllable amplifier, one of multiple switch filter circuits is selected, and other amplifiers areturned off, only one amplifier supplies the power at the same time, so that the power consumption is reduced; furthermore, the Gallium-Arsenide switch with small current is selected, and the power consumption is further reduced.