Single snorkel refining furnace （SSRF） is new equipment in steel refining which is invented from China. It is known by more and more people as simple construction， high production efficiency and little splash in vacuum refining. It has been used to produce bearing steel， ULC steel and non-oriented electrical steel domestically. SSRF has good metallurgical properties at deeply decarburization， desulfurization， deoxidation， remove inclusions and so on， and achieved good refining results. The operating parameters such as gas flow rate， plug location， inner diameter of snorkel and immersing depth of snorkel in SSRF were widely study by water model and mathematical model. The results of aforementioned study can play important reference and instructive role for commercial production. In this paper， REDA as a similar equipment from construction and principle that invented in Japan was also discussed. It has been applied to produce ULC steel and stainless steel.