Abstract: A method of multichannel joint frequency and Direction Of Arrival (DOA) estimation is proposed for the signal with wide frequency band. Under the condition of sub-Nyquist spatio-temporal sampling, the method can provide unambiguous frequency and DOA estimation. According to the space-time two-dimension unambiguous array presented in the paper, the expanded dimension of multiple sampling channels solves the issue of temporal undersampling, and the expanded dimension of multiple snapshot channels overcomes the issue of spatial undersampling. Using the temporal filtering, the estimated frequency and DOA are cascaded, and the pairing of the estimated frequency and DOA is automatically determined. In addition, the spatio-temporal cascaded method can avoid the 2-D spectral peak searching and high-dimensional eigenvalue decomposition, which reduces the computational complexity. Simulation results demonstrate the effectiveness of the novel method.