The invention discloses an alkane/napthene system separation solvent screening method, which belongs to the field of chemical separation. The method is characterized in that a functional group is screened to synthesize a predetermined solvent; using a real solvent for simulating a conductor-like screening model ro obtain the chemical potential of alkane and napthene in the solvent and the pure components; according to the chemical potential, an theatrical value of the infinite dilution activity coefficient of the alkane and napthene in the solvent can be obtained, and is subjected to fitting, a fitting value empirical correlation of the infinite dilution activity coefficient of alkane and napthene can be obtained; the fitting value of the infinite dilution activity coefficient of certain alkane and napthene in the solvent to be separated is obtained according to the empirical correlation, relative volatility of the alkane and napthene in the predetermined solvent can be obtained, under the condition that the relative volatility satisfies the requirement, the solubility of alkane and napthene in the predetermined solvent is calculated, if the solubility satisfies the requirement, the predetermined solvent is the separation solvent. The method has the advantages of rapidity, simpleness, accuracy and high efficiency.