ULP series of ultra-low pressure aromatic polyamide compound membrane element newly developed by Vontron Membrane Technology Co., Ltd. can work under ultra low pressure to reach as high permeate flow and rejection same as regular low-pressure membrane element, and is applicable to desalination of surface water and underground water. It operates under approximately two thirds of the operating pressure of regular low-pressure composite membranes, which can decrease the investment costs for such relevant facilities as pumps, pipelines, and containers, etc. and the operating cost for the RO system, thus increasing the economic efficiency.