By using a very simple liquid model a theoretical equation between the capacity factor k' and the molecular parameters of solutes, solvents etc, can be derived.From this equation two linear relationships anion; silicagels with various surface aroas can be derived:namely, the linear relationship between the logarithm values of k' of various solutes on two silica gels with different surface areas and the linear relationship between the logarithm values of k' of a solute and logarithm values of surface areas of silica gel.Micropartiole silica YWG-5 with various surface areas produced by Qindao Marine Chemical Plant was used and k's of solutes, including aromatic hydrocarbons, halogenated compounds, aromatic ethers and aromatic esters, were determined with home-made HPLC instrument using heptane as eluant. The linear relationships egperimontally obtained are in good agreement with the theoretical prediction.