Array processing has played an important role in many diverse application areas such as radar, sonar, radio astronomy, seismology, tomography, speech, communication etc. As early as World War II,phased array radars have been used. Most modern radar and sonar systems rely on antenna arrays or hydrophone arrays as an essential component to estimate the direction of arrival of desired and interference signals, or do spatial filtering. Seismic arrays are widely used for oil exploration and detection of underground nuclear tests. Smart antenna is a key technique in third generation wireless communications to improve the user capacity and increase the cellular radius, so as to decrease the cost. Microphone arrays are used in speech detection and enhancement by spatial filtering, which will be useful in hearing aid and speech input. In this report, we mainly discuss some key techniques on wideband array signal pro- cessing and some relevant topics.