The invention provides a high-lance-position vacuum refining method based on a coherent jet top lance. The coherent jet top lance is provided with a powder passage located at the center, a main oxygen passage located on the periphery of the powder passage and an auxiliary oxygen passage located on the periphery of the main oxygen passage; and during RH vacuum refining, oxygen enters from the main oxygen passage and the auxiliary oxygen passage to form a main oxygen flow and an auxiliary oxygen flow respectively, powder is injected into molten steel together with the main oxygen flow under the sweeping and protection of the main oxygen flow, the main oxygen flow impacts the molten steel and reacts with carbon in the molten steel to generate carbon monoxide, and carbon monoxide escaping from the molten steel is subjected to secondary combustion with the coherent surrounding accompanying auxiliary oxygen flow to heat a vacuum tank so as to reduce temperature drop of the molten steel. According to the invention, the auxiliary oxygen flow forms the surrounding accompanying flow outside the central supersonic jet flow, so that the expansion and attenuation of the central supersonic jet flow are smaller, the supersonic jet flow is longer, the penetration depth and stirring strength of the oxygen jet flow to a molten bath are increased, a lance position is raised to reduce splashing of the molten steel and slag sticking to a lance head, and the service life is prolonged.