Abstract: The state and the direction of research in speech separation technique,including computational auditory scene analysis (CASA) and blind source separation (BSS),are reviewed.Computational auditory scene analysis is a processing mechanism that simulates human auditory system by computer.CASA is classified as data-driven CASA and schema-driven CASA.The information direction flowing of data-driven CASA is bottom-up and that of schema-driven CASA is integrating bottom-up and top-down.Finally,it is pointed out that the speech separation model of information bi-direction flowing of CASA is the dominant pattern of CASA in the future,and the speech separation method based on integrating audition and vision in order to improve effect of speech separation is one of the directions of research in the future.Furthermore,it is pointed out that the under-complete,the nonlinear and the non-stationary BSS problems are needed to study further,and the speech separation technique based on integrating CASA and BSS is the hot issue of research in the future.