La/Y-codoped microporous organosilica membranes were successfully fabricated by sol-gel procedure with 1,2-bis(triethoxysilyl)ethane (BTESE) as silica precursor for efficient desalination. The rare earth elements were confirmed to be doped into silica frameworks during the sol-gel procedure by various characterizations, which would decrease particles size and size distribution of BTESE-derived sols and form hydrothermally stable Si-O-RE (RE for La and Y) bonds. It could significantly influence membrane surface morphology, microstructure properties and hydrophilcity of La/Y-codoped membranes, and then improve their desalination performance. Under the optimized preparation conditions, La25Y75-SiO2 (La:Y = 25:75, mol%) membranes exhibited the highest water flux of 10.3 kg m(-2)h(-1) and NaCl rejection of nearly 100% towards 3.5 wt% NaCl feed solution even at room temperature of 25 degrees C. It was attributed to strongest hydrophilcity, finest microstructure, and lowest mass resistance of water permeation for La25Y75-SiO2 membranes. Moreover, such these organosilica membranes demonstrated good stability for 200 h simulated seawater desalination tests without any significant changes of separation performance and promising hydrothermal durability under various salts solutions with different concentrations at 25-60 degrees C.