NOVELTY - A methane is made into sulfur-free natural gas by delivering prepared methane through control valve into solid-gas separating device; using desulfurizing tower to remove sulfur-contained gas from processed methane; using gas compressor to press processed methane and push it backward; letting processed methane flow through an absorption tower to absorb carbon dioxide gas from methane by way of solution replacement; and cooling and dehydrating processed methane; and using ultrafiltering device to filter processed methane.    USE - Method for making methane into sulfur-free natural gas (claimed).    ADVANTAGE - The method can obtain high purity methane of 85-99%; is suitable for industrial production at high efficiency; and can improve the utilization of methane materials.    DETAILED DESCRIPTION - The methane is made into sulfur-free natural gas by:    (A) delivering prepared methane through control valve into solid-gas separating device, controlling pressure at 0.5-2 MPa, separating gas from impurities such as dust in methane, letting methane gas containing impurities flow into separating device to separate solid from gas and separate liquid from the gas, letting impurities such as dust discharge from an outlet in lower part of the separator, and letting separated methane gas flow out from separating device;    (B) using desulfurizing tower to remove sulfur-contained gas from processed methane;    (C) using gas compressor to press processed methane and push it backward, and controlling flow rate at 8-20 m/second;    (D) letting processed methane flow through an absorption tower to absorb carbon dioxide gas from methane by way of solution replacement;    (E) cooling and dehydrating processed methane, and controlling its water content at relative humidity of below 80%; and    (F) using ultrafiltering device to filter processed methane to remove other impurities and obtain desired sulfur-free natural gas.    An INDEPENDENT CLAIM is included for a methane preparing device comprising separating device for separating impurities and flammable gas from methane; desulfurizing tower connected to output end of the separating device; pressing device connected with the desulfurizing tower; absorbing tower connected to the output end of the pressing device; cooling and dehydrating assembly connected with the absorption tower; and ultrafilter connected to cooling and dehydrating assembly.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram illustrating a method for making methane into sulfur-free natural gas. (Drawing includes non-English language text).