NOVELTY - Low-coal methane (CH4) is prepared by drying 3-10 low coal at 110-200 degrees C until water content is reduced to 5-8 wt.%, subjecting to pyrolysis at 300-700 degrees C and normal pressure to obtain pyrolyzed semi-coke, performing methanation reaction at 750-930 degrees C and 3-5 MPa in which carbon and hydrogen gas (H2) are reacted by semi-coke gasification to form CH4-rich gas, performing gasification reaction on remaining residue, generating gas-containing tar by pyrolysis reaction, cooling, separating, and purifying, and subjecting generated pyrolyzed gas to carbon monoxide (CO) conversion to obtain CH4.    USE - A preparation of low-coal methane (claimed).    ADVANTAGE - Low-coal methane process has high thermal efficiency and low hydrogen consumption and methanation reaction rate.    DETAILED DESCRIPTION - Low-coal methane (CH4) is prepared by drying 3-10 low coal at 110-200 degrees C until water content is reduced to 5-8 wt.%, subjecting to pyrolysis at 300-700 degrees C and normal pressure to obtain pyrolyzed semi-coke, performing methanation reaction at 750-930 degrees C and 3-5 MPa in which carbon and hydrogen gas (H2) are reacted by semi-coke gasification to form CH4-rich gas, performing gasification reaction on remaining residue, generating gas-containing tar by pyrolysis reaction, cooling, separating, and purifying, subjecting generated pyrolyzed gas to carbon monoxide (CO) conversion to obtain CH4 used as recycled gas (I), carbon dioxide and H2-rich gas used as product, performing pyrolysis to raw material coal at 500-800 degrees C by indirect heat exchange, generating CH4 gas by cycling hydrogen and cold water heat exchange at 30-150 degrees C via cold methanation, purifying and separating to obtain synthetic natural gas and recycled gas (II), subjecting gasification reaction product to indirect heat exchange with raw material coal at 500-700 degrees C, purifying, transforming and decarburizing to obtain recycled gas (III), mixing recycled gas (I)-(III) to obtain recycled H2 gas, and circulating recycled H2 gas as gasifying agent into methanation reactor.