Abstract: Coal mining leads to ventilation air methane emission, which not only pollutes the environment but also runs counter to "carbon neutral, carbon peaking" in China.This study prepared a sub-nanometer Pd cluster catalyst encapsulated in the Silicalite-1 molecular sieve support by the one-pot hydrothermal method, which has excellent catalytic activity and stability in methane catalytic oxidation reaction.The physical phase composition, pore structure parameters, microscopic morphology, chemical state and the present state of the active component Pd of the catalytic material were characterized by XRD, BET, SEM, XPS and TEM.This study then investigated the effects of active component loading, air velocity, reaction temperature and other conditions on the catalytic performance.The experimental results showed that the one-pot hydrothermal method successfully encapsulate Pd clusters within the pores of Silicalite-1 molecular sieve carriers to prepare highly dispersed sub-nanometer Pd cluster catalysts; the catalytic performance first increases and then decreases with the increase of Pd loading.This was due to the agglomeration effect between Pd atoms, resulting in the encapsulation of some Pd atoms and reducing the contact area between the active component and the reactants; in addition, using Silicalite-1 molecular sieve as a carrier can promote the conversion of active site skeletal oxygen to surface hydroxyl groups, which contributes to the catalytic oxidation of methane.The catalyst in this study excels existing methane catalytic process for its high catalytic activity, simple preparation, and low processing cost.