The efficient utilization of cellulose for producing methane fuel is of great significance to the sustainable development of human society. In this article, nanoporous Ru catalyst was employed for the transformation of cellulose to methane under the relatively mild conditions of 220 °C and initial H2 pressure 0.5 MPa, and the conversion of cellulose is 75.8% with 82.2% selectivity of methane using H2O as solvent. The catalyst was reused for 10 times, and the highest yield of CH4 was 79.5%. The reaction mechanism of cellulose transformation and structure change of cellulose in the process were studied. Results showed that cellulose transformation consist of two parts, which are acid-catalyzed hydrolysis process and nanoporous Ru-catalyzed hydrogenation process. Therefore, a bifunctional nanoporous Ru was designed with Brønsted acid sites by Mo, W, Re and V doping. The conversion rate of cellulose was significantly increased and yield of methane increased by 9.6% with the bifunctional nanoporous Ru.