Continuous dark fermentative hydrogen production technology is suitable for commercial application. This review summarized several main basic factors influencing the operation of the reactor, followed by some suggestions and outlooks. The factors included temperature, pH, HRT and COD were briefly introduced and discussed. This review demonstrated that the optimal value of a given factor under different conditions was great different. This indicates that reactor operation is affected by many factors and sensitive to environmental change. To make the technology more feasible into practice, deeply understanding about the characteristics and rules of the operation is necessary. Thus more researches in this respect are recommended.