Flexibility and simplicity are key points in designing a digital quadrature demodulator, which is an important part of wideband radar digital receiver. In this paper, we proposed a new implementation of digital quadrature demodulation based on nonuniform-sampling, which is evolved from second-order sampling and multiphase filter. The structure of nonuniform-sampling was presented, and its effectiveness was verified by simulation results. Compared with low-pass filter and multiphase filter, nonuniform-sampling obtains more optimized structure and better performance in real-time processing. This novel approach will offer potential for better resolution in designing a wideband radar digital receiver.