Investigating the characteristic of earthquake source more accurately and faster is required to mitigate earthquake hazard and improve the understanding of the mechanism of earthquake source. In this work, I develop a new method: multi-array local back-projection (MLBP). Local back-projection potentially resolve the rupture process of large earthquakes faster and more accurately. Multiple arrays are combined to increase the stability and accuracy of back-projection results. The method are successfully applied to large earthquakes from M 6 to M 9 using the existing seismic stations in California and Japan. We also propose a tsunami early warning approach based on the muti-array local back-projection method.