Based on non-uniform L - shaped array, a new method is presented to estimate the frequency and 2 - D arrival angles of coherent signals over a wide frequency band, which is called joint smoothing DOA (JSDOA) algorithm. The smoothed DOA matrix is constructed by using the temporal and spatial data of L -shaped array, and then 3 - D parameters of coherent signals can be obtained via the analysis of its eigenvalue. The algorithm is precise in estimating 3 - D parameters of coherent signals with same digital frequency, thus avoiding the loss of array aperture with smaller computational load and parameters paired automatically. The simulation results confirm its effectiveness.