Abstract: This paper proposes two algorithms for achieving blind spectrum sensing and two-dimensional direction of arrival (DOA) estimation in an arbitrary two-dimensional array receiver with sub-Nyquist sampling. The two proposed algorithms utilize the Fourier series coefficient matrix of the periodic signal of modulated wideband converter (MWC) to determine the sub-band positions of signal spectra, and then take advantage of the signal model derived from the two-dimensional array to estimate the spatial phases which contains two-dimensional DOA. Based on the estimated information, the sub-band spectra are reconstructed so that carrier frequencies can be estimated with high precision. Finally, the azimuth- and elevation-angles of signals are estimated through spatial phases, respectively. Simulation results verify the effectiveness and high robustness of the proposed sub-Nyquist sampling receiver and the algorithms under environment with a low signal-to-noise ratio.