This paper proposes a novel photo-assisted microwave frequency measurement strategy with proved real-time performance to tackle with the defect of low real-time performance in conventional segmented photonassisted microwave frequency measurement. The microwave signal to be measured passes through the upper and lower branches of dual- parallel Mach- Zehnder modulator (DPMZM) and simultaneously modulates the two branches of laser with different wavelengths. The modulated output laser of the two branches then demodulates the signal to be measured by single-mode fiber dispersion and photoelectric converter. Different bias voltages are provided to the two branches of DPMZM so that the upper branch measurement range is large, and the lower branch measurement range is small, respectively. Therefore, the frequency of the microwave signal to be measured can be obtained by a two-step calculating process in electric domain. This method eliminates the need of adjustment and recalibration of the device and thus achieves better real- time performance. Experimental results show a measurement time of less than 70 μs with resolution of ±0.4 GHz in rang of 4.3~18.7 GHz.