This paper presents the design and fabrication of a compact 4-8GHz sweep frequency source at C-band with a hybrid frequency synthesizer technology. With DDS used as PLL’s reference, the frequency step size is as small as 3×10^-4 Hz and the measured 1 kHz offset phase noise is-91.79dBc/Hz at 4GHz. This frequency sweep source has advantages of wide bandwidth, low phase noise, small frequency step size, low spurious, fast tuning speed, small size and low power consumption. So it is suitable for wireless hand-held test equipment and communication equipment.