Abstract: The disclosure discloses a compound milk-beer lyophilized fermentation microorganism agent as well as a preparation and application thereof. The microorganism agent comprises a lyophilized microorganism agent of Kluyveromyces marxianus var. marxianus A3 and a lyophilized, microorganism agent of Saccharomyces cerevisiae TR2, wherein the ratio of the viable count of Kluyveromyces marxianus var. marxianus A3 to the viable count of Saccharomyces cerevisiae TR2 in the compound milk-beer lyophilized fermentation microorganism agent is (1.5-2.5):1. The compound fermentation microorganism agent can be applied in production of milk beer, and the product quality and production efficiency of milk beer are improved compared with single strains.