The invention relates to an external furnace refining technology for a bottom leakage steel ladle of 10 to 30 tons, in particular to the external furnace refining technology for the bottom leakage steel ladle of 10 to 30 tons. A method of the invention mainly adopts an early electroslag protection technology, an electroslag heating technology, a long-term argon blowing refining technology, a plugstick adhesion prevention technology, a plugstick deformation prevention technology, an air coiling and mingling prevention technology, a furnace brick lining protection technology, etc. The technologysuccessfully solves the problems that the argon blowing refining time is not enough, air coiling and mingling and plugstick deformation are prevented, the steel ladle can not be opened, etc. The technology reasonably designs the electrical heating output power, an argon blowing position, the argon blowing amount and the argon blowing time, effectively carries out degassing, desulphurization, impurity removal, etc. to molten metal and remarkably improves the quality of molten steel. Through carrying out electroslag hating to the steel ladle of 10 to 30 tons, the technology carries out argon pumping and refining for a long time, and uses graphite as electrodes; and the output power can meet the power needed when a temperature reduction speed is the rapidest and ensure that the temperature of the molten steel is stable and is not reduced.