In this study an efficient strategy,i.e.,sequential dark and photo fermentation,for significantly increasing biohydrogen production from sewage sludge was reported.Without addition of pure hydrogen producer,the effect of different pH on hydrogen production from sewage sludge in dark fermentation was compared.The maximal hydrogen yield of dark fermentation was observed at pH 11.It was observed that pH 11 in dark fermentation showed much higher solubilization of sludge main particulate organic matters,consumption of solubilized organic materials and acidification of hydrolyzed products,which were of benefit to the hydrogen production in dark fermentation.The fermentation liquid from dark fermentation was further used by photosynthetic bacteria(PSB)to produce hydrogen.The NH4 + in dark fermentation was firstly removed before photo fermentation,and the reason was also studied.Finally,the total hydrogen production from sequential dark and photo fermentation was calculated,which reached 30 ml H2/g-COD.