The invention discloses an emulsion drilling fluid with high density and low oil-water ratio for a shale horizontal well. The emulsion drilling fluid is prepared from raw materials in parts by weight as follows: 180 parts of 3# white oil, 120 parts of a 30% calcium chloride solution, 2-5 parts of a main emulsifier, 4-8 parts of an auxiliary emulsifier, 12-18 parts of a reversible emulsifier, 5-10 parts of calcium oxide, 2-5 parts of organic soil, 3-8 parts of a blocking agent, 0.5-3 parts of an extracting agent, 6-12 parts of calcium carbonate and 0-800 parts of barytes, wherein the main emulsifier is prepared from tall oil fatty acid and maleic anhydride, the auxiliary emulsifier is prepared from high-level fatty acid salt and high-level fatty acid polyol ester, the reversible emulsifier is prepared from methyl 9-octadecenoate and hydroxyethyl ethylenediamine, and the extracting agent is prepared from styrene, methyl methacrylate and hexadecyl acrylate. The oil-water ratio is 6:4, and the emulsion drilling fluid has higher inhibition dispersibility and blocking capacity, good lubricating property and good heat-resisting property and can be suitable for meeting the drilling requirement of a horizontal section of the shale deep well.