Some perfluoro-amide bonded YWG with different amount of organic coverage (3.48%,9.3%,12.67%,18.19%) have been prepared from YWG silica, with various amount of perfluorooaprylamido-propyl-triethogy-silane in CF₂ClCFCl₂ solution, perfluorooaprylamido-propyl-monoethogyl was proved to be the group bonded onto the surface, its surface concentrations on these packings are 0.24, 0.71, 0.88, 1.26 μM/m² respectively. YWG silica contains the higher concentration of the fluorinated group will show the weaker polarity. These fluorinated YWG silica samples give rise to a much shorter retention time for polar steroid compounds. This effect is more obvious in the case of compounds with a longer retention time. As the flouoro-amide group is hydrophobic in nature, so it not only modifies the peak symmotry and tailing factor, but also shows good selectivety towards some compounds of oholestene series, which could not be separated on YWG silica column under normal conditions.