In the recent years, hydrogen and synthesis gas are major raw materials for petroleum, gas and petrochemical industries. Demands for these gases all days are increased. By considering consuming of hydrogen and synthesis gas in different industries, it is mandatory to investigate economic and environmental friendly process for producing thesis gases. Various methods for production of synthesis gas are: Coal gasification, Steam reforming of methane, Partial oxidation of methane, Auto thermal reforming of methane, Dry reforming of methane and Tri reforming of methane. In this work, several researches about dry reforming of methane plus coupling of several methods have been introduced. Investigated results indicate that dry reforming of methane produces synthesis gases for downstream process by reduction of green house gases emission to environment can be good alternative of currently process.