TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: Producing hydrogen comprises: (a) inoculating the tetraselmis: adding Kangweifang culture medium into the flat biologic photo reactor, inoculating the tetraselmis in exponential phase with the inoculum density of 0.5-1000000 cell/ml; (b) culturing the tetraselmis: acclimatizing the inoculated tetraselmis to the culturing conditions with the culturing temperature of 22-30 degrees C, the light intensity of 80-150 micro E per square meter per second and the lighting ration of 12-14:10-12, leading in the mixture of the carbon dioxide and air with the concentration of 2-5% V/V, making the input quantity be 0.2-1vvm, (c) producing hydrogen when the algae density in the flat reactor is 6-10000000 cell/mL, sealing the reactor in the hydrogen producing process, leading in nitrogen for 10-20 minutes for achieving anaerobic state, keeping the reactor in dark place for 4-12 hours for dark induction so as to sufficiently express the hydrogenase of tetraselmis, (d) after the dark induction, adding the uncoupling agent carbonylcyanide-3-chlorophenylhydrazone (CCCP) with the final concentration of 7.5-15 micro M into the algae liquid, using sodium hydroxide (NaOH) and HCl to adjust the pH value of the algae liquid to 7-8, exerting the illumination of 100-150 micro E per square meter per second to the flat reactor 20-30 after the injection of uncoupling agent for continuously producing hydrogen through illumination, and (e) using a pipe to lead the hydrogen produced by the algae liquid in the photo-reactor into the hydrogen electrode of the basic oxyhydrogen fuel battery, making the fuel battery consume the hydrogen continuously so as to keep low partial pressure of hydrogen in the photo-reactor system, remove the inhibition of product and improve the hydrogen output, using a monitoring system to record the current variation because the hydrogen produced by the system is consumed by the fuel battery. In the hydrogen producing process in step (d), a mini vacuum pump is used for making the gas above the algae liquid in the photo-reactor circulate; the vacuum pump is used for leading the gas above the algae liquid into the algae liquid so as to guarantee the anaerobic condition in the process of producing hydrogen. The light intensity needed in the culturing stage of step (b) and the hydrogen producing stage in step (d) is provided by 5-10 fluorescent lamps; the irradiation method is single side irradiation; the specific value of the light intensity is measured by a irradiatometer; and the desired light intensity is achieved through adjusting the distance between the light source and the reactor.