The invention relates to a high-efficiency and environmental-protection method for removing tiny amount of water from highly viscose mineral oil. An alkyl metal compound is dropwise added to the mineral oil under stirring to make the alkyl metal compound react with the tiny amount of water in the mineral oil in order to remove the tiny amount of water. The method for removing water from mineral oil mainly uses the high reaction degree of the alkyl metal compound and water, and substances obtained after the reaction with water are a tiny amount of byproducts having no negative influences on the performances of a catalyst, and do not need to be removed, so the process is saved, and the energy consumption is reduced.