Abstract: Based on the orthogonality of the subspace,a fast algorithm for wideband direction-of-arrival(DOA) estimation is proposed.It estimates the DOAs by testing the orthogonality and does not require any preprocessing for initial values.Only a few frequency components having high SNR of the sources are chosen for processing,the computational complexity is effectively reduced.Meanwhile,the fast algorithm has a high resolution and can be used with an arbitrary array.Computer simulations demonstrate the efficacy of the proposed algorithm.