In this research study, a self-developed gas seepage experimental system was used to carry out experiments on methane flow with alumina films under different rarefaction degrees conditions, in order to examine the intra-nanopore methane flow law. Then, based on the experimental results under the conditions which considered the slip boundary, a new intra-nanopore methane flow equation with a correction term was established. The change law of the ratio between the equivalent permeability and the Darcy permeability, Kp, was studied under the conditions of different rarefaction degrees. The research results showed that the alumina film was a type of ideal material for the study of methane flow law in nanoscale pores. It was found that, with the increase of the rarefaction degree, the ratio between the equivalent permeability and the Darcy permeability, Kp, gradually increased. With the increase of the rarefaction degree, multiple flow mechanisms were found to exist in the methane flow, including Darcy flow, slip flow, transition flow, and free molecular flow. The research results provided theoretical support for clearly revealing the flow mechanisms of methane and shale gases. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.