SFE is a technique using supercritical fluids as extractants, typically carbon dioxide. Supercritical CO2 becomes gaseous after depressurization, which can be easily eliminated from a flow system. Thus, SFE is very suitable for online coupling with LC. The first online SFE-LC system dates back to 1983 and this online technique has been widely applied to the analysis of a wide range of analytes so far, which was proved rapid, selective and environmentally friendly. In recent years, there have been a few researches related to efficient online SFE-LC systems. For instance, online hyphenation of SFE with two-dimensional high performance liquid chromatography/mass spectrum has been developed and at least 73 components in a plant sample were resolved with the calculated peak capacity of 1643, which showed the advantage of powerful resolving potential in separation and identification. Another example is the online hyphenation of SFE to UPLC, which makes the analysis procedure four times faster than the traditional SFE-LC method.