NOVELTY - Fermentation hydrogen production involves pumping organic wastewater in a reactor added with anaerobic hydrogen production bacteria, collecting gas, and separating hydrogen; removing microbiological cells from fermentation solution; pumping biological hydrogen production fermentation solution into a diluting compartment of a bipolar membrane electrodialyzer to perform electroosmosis separation, and when pH value of fermentation solution is 4.8-5.5, pumping fermentation solution into reactor to mix with organic wastewater to continuously produce and ferment hydrogen.    USE - Method for fermentation hydrogen production (claimed).    ADVANTAGE - The method can improve hydrogen yield by 1.3-1.5 times, control pH value to 4.8-5.5 without addition of alkali, and improve the usage rate of substrate to 50-100% and biomass to 80%.    DETAILED DESCRIPTION - Fermentation hydrogen production comprises:    (A) pumping organic wastewater in a reactor added with anaerobic hydrogen production bacteria (1-5 g/L) to perform anaerobic hydrogen production fermentation at controlled temperature of 35 plus minus 1 degrees C, collecting the gas, and separating the hydrogen, where the organic wastewater has chemical oxygen demand of 5-20 g/L and pH value of 5-7, and the fermentation liquid in the anaerobic fermentation reactor has pH value of 4-5;    (B) removing microbiological cells from fermentation solution via a cell separating device in the anaerobic fermentation reactor;    (C) pumping biological hydrogen production fermentation solution into a diluting compartment of a bipolar membrane electrodialyzer, applying 0.5-3 V of direct current voltage to perform electroosmosis separation, and when the pH value of the fermentation solution reaches 4.8-5.5, pumping the fermentation solution into the anaerobic fermentation reactor to mix with the organic wastewater in the fermentation reactor; and    (D) continuously producing and fermenting hydrogen, collecting the gas, and separating the hydrogen.