Abstract: Based on the designed uniform linear array, the passive tracking for underwater broadband targets is conducted as follows: using the spatial resample method for calculating the element weight coefficients of a constant beam-width array to generate a focusing matrix, which maps the sub-band signals of different frequency bands of the broadband signal on the same reference frequencies, then averaging the signal power spectral density matrix of all frequency components and combining with MUSIC algorithm to estimate the orientation information of the target and to realize the passive tracking of underwater broadband target. Simulation of using this method has been done. The result shows that for a single broadband target this method has the stable tracking performance on a small aperture array, and has a certain effect on angle passive distinguish of multi-targets.