Full-duplex, which aims to simultaneously transmitting and receiving over the same band, together with phased array antennas play fundamental roles in next-generation wireless communication systems. The combination of them, phased array fullduplex, is widely accepted as a promising way for realizing practical full-duplex communications. However, diversified application scenarios and rapidly grown system complexity hinder the development of PAFD. In this work, we present a spatial domain selfinterference suppression method for the implementation of fullduplex in digital phased array architectures. By taking advantage of the flexibility of fully-digital phased array, a novel computation framework is constructed to effectively optimize the transmitting beamforming weights in order to maximize the desired beamforming gains of the transmitting sub-array while simultaneously reducing the self-interference received by receiving sub-array. Our work demonstrates the capability of spatial domain methods in digital phased array and paves the way for practical full-duplex communications.