The design and establishment of a new kind of high speed quenching experimental system are reported. The ejecting speed of the ejector can be adjusted continuously and quenching speed can be measured accurately. As the setup is used to study the ultra rapid cooling of small sample in liquid Nitrogen (LN 2), the high quenching speeds and the high cooling rates are reached. The maximum boiling heat fluxes and maximum cooling rates are increased dramatically as the results of decreasing of sphere diameters, or increasing of LN 2 subcoolings.