The present invention relates to a catalyst used for producing dimethylether, a method of producing the same, and a method of producing dimethylether using the same. More particularly, the present invention relates to a catalyst used for producing dimethylether comprising a methanol synthesis catalyst produced by adding one or more promoters to a main catalyst comprised of a Cu—Zn—Al metal component and a dehydration catalyst formed by mixing Aluminum Phosphate (AlPO4) with gamma alumina, a method of producing the same, and a method of producing dimethylether using the same, wherein a ratio of the main catalyst to the promoter in the methanol synthesis catalyst is in a range of 99/1 to 95/5, and a mixing ratio of the methanol synthesis catalyst to the dehydration catalyst is in a range of 60/40 to 70/30.