We propose a photonic-assisted single system for measuring the frequency and phase noise of microwave signals in a large spectral range.Both the frequency and phase noise to be measured are extracted from the phase difference between the signal under testing and its replica delayed by a span of fiber and a variable optical delay line(VODL).The system calibration,frequency measurement,and phase noise measurement are performed by adjusting the VODL at different working modes.Accurate frequency and phase noise measurement for microwave signals in a large frequency range from 5 to 50 GHz is experimentally demonstrated.