NOVELTY - A catalyst for preparing methane and co-producing low carbon mixed alcohol from synthesis gas, comprising copper, cobalt, auxiliary agent supported on a carrier is new.    USE - As catalyst for preparing methane and co-producing low carbon mixed alcohol from synthesis gas, where the mixed alcohol includes methanol, ethanol, propanol, butanol and isobutanol (claimed).    ADVANTAGE - The raw material of the catalyst has the wide variety of sources and can be derived from coal and biomass. The catalyst has a low cost; is prepared by simple preparation method; has high efficiency; and is suitable for continuous large-scale production.    DETAILED DESCRIPTION - A catalyst for preparing methane and co-producing low carbon mixed alcohol from synthesis gas, comprising copper, cobalt, auxiliary agent supported on a carrier of formula CuCoM'A'/C', where the content of the Cu (counted by metal element) in the catalyst is 1-90 (preferably 20-50) wt.%, the content of the Co (counted by metal element) in the catalyst is 1-90 (preferably 20-50) wt.%, the content of the component M' (counted by metal element) in the catalyst is 0-90 (preferably 1-15) wt.%, the content of the component A' (counted by metal element) in the catalyst is 0-25 (preferably 0.01-5) wt.%, and the content of carrier component C' in the catalyst is 10-95 (preferably 60-75) wt.%, is new.    M'=additive (preferably mixture of Zn, Cr, Fe, V or Mn, especially Mn and/or Fe);    A'=additive (preferably Li, Na, K, Mg, Ca, Sr or Ba);    C'=carrier component (preferably Al2O3, ZrO, SiO2 or TiO2).    INDEPENDENT CLAIMS are included for the following:    (1) a preparation method of the catalyst by using impregnation method involving a) according to the weight ratio of each component in the catalyst, roasting and purifying the carrier component C' at 400-700 degrees C for 1-10 hours, cooling; b) performing equivalent-volume impregnation on the samples obtained in the step a) by the aqueous solution containing copper, cobalt, metal ion of component A' and component M' for 2-12 hours; c) drying the samples obtained after impregnation in step b) by distillation at 70-90 degrees C, drying at 100-150 degrees C, roasting at 400-800 degrees C for 1-20 hours, to obtain the catalyst; and    (2) preparing methane and co-producing low carbon mixed alcohol from synthesis gas involving reacting synthesis gas in the reactor containing the catalyst to prepare methane and co-produce low carbon mixed alcohol, where the temperature (T) of reaction of preparing methane and co-producing low carbon mixed alcohol from synthesis gas is 200-400 degrees C, the reaction pressure (P) is 0.5-10 MPa, the reaction volume space velocity (liquid hourly space velocity (LHSV)) is 1000-40000 per hour.