Abstract: Lau basin, one of active marginal basins in Southwest Pacific, belongs to a relatively simple intra-ocean marginal basin, which has been regarded as an ideal place for testing the theories of plate tectonics and seafloor spreading. The conclusions achieved by studying on lava chemistry and petrology play a significant role in evaluating the origin of ophiolite and ocean crust model in normal mid-ocean ridge setting. In addition, further studying on the genesis of sulfide deposits outcropped in Lau basin is helpful to establishing a reasonable prospecting model for similar deposit in the continent. Based on reviewing geology, structural geology, petrology and hydrothermal deposits in the Tonga arc-Lau basin system, this paper points out some important scientific problems which need to be further solved, and proposes several key orientations for further study. That studying on the integrated tectonic-magmatic-hydrothermal system is helpful for us to improve China's basic research level about back-arc basin system by using rock and sulfide samples which were collected during the global expedition (Cruise ID:DY115-19) performed by China, and will make a greater contribution to Earth sciences.