Based on analyzing the latest development trends of digital array radar, in this paper, it is summarized the problems that need to be solved in the aspects of modulation freedom, signal characteristic processing, parameter control and algorithm acceleration in the development of digital array technology to “wideband, discrete, intelligent and flexible”. Meanwhile, the suitability, advantages and disadvantages of microwave photonic technology are discussed. For pushing forward the progress of practical implementation, the prospects of several microwave photonic technologies in digital phased array radar system are analyzed, including photonic analog-to-digital conversion, photonic quadrature demodulation, photonic arbitrary waveform generation, RF bus, etc.