NOVELTY - Producing hydrogen by using photosynthetic bacteria comprises culturing the photosynthetic bacteria for producing hydrogen under initial incident light irradiation of illumination intensity I1 and under non-standing state; and isolating the produced hydrogen from the culture system.    USE - The methods are useful for producing hydrogen by using photosynthetic bacteria, and for improving the hydrogen producing speed of photosynthetic bacteria (all claimed).    ADVANTAGE - The method for producing hydrogen by using photosynthetic bacteria is effective and rapid and has high substrate conversion rate.    DETAILED DESCRIPTION - Producing hydrogen by using photosynthetic bacteria comprises (a) culturing the photosynthetic bacteria for producing hydrogen under initial incident light irradiation of illumination intensity I1 and under non-standing state, where the illumination intensity I1 of the initial incident light satisfies the conditions as follows: (i) I1 is greater than I0, in which I0 is the optimum illumination intensity of the initial incident light when standing and culturing; and (ii) under the illumination intensity I1, the practical illumination intensity I1' of at least 70% zone (or volume) in the culture system is greater than or equal to the practical illumination intensity I0' of the same zone (or volume) under standing culture; and (b) isolating the produced hydrogen from the culture system. An INDEPENDENT CLAIM is a method for improving the hydrogen producing speed of photosynthetic bacteria by (a) measuring the illumination intensity of optimum initial incident light under the condition of standing and culturing the photosynthetic bacteria, recording into I0, and measuring the illumination intensity of the initial incident light into I0, and then recording the optical density (OD) value of the standing culture system under the condition of standing and culturing the photosynthetic bacteria into OD0; and then determining the practical illumination intensities of different zones in the standing culture system according to the illumination intensity I0 of the optimum initial incident light under standing culture and the OD value of the standing culture system; (b) measuring the OD value of the non-standing culture system under the condition of non-standing and culturing the photosynthetic bacteria, recording into OD1; (c) according to the OD value of the non-standing culture system, determining illumination intensity I1 of the optimum initial incident light when non-standing and culturing according to the OD value of the non-standing culture system, where the illumination intensity I1 of the initial incident light satisfies the conditions as follows: (i) I1 is greater than I0, in which I0 is the optimum illumination intensity of the initial incident light when standing and culturing; and (ii) under the illumination intensity I1, the practical illumination intensity I1' of at least 70% zone (or volume) in the culture system is greater than or equal to the practical illumination intensity I0' of the same zone (or volume) under standing culture; and (d) culturing the photosynthetic bacteria under the initial incident light irradiation of illumination intensity I1 and under non-standing state.