An object of the present disclosure is to find a method in which a result of liquid chromatography can be predicted with high accuracy for a wide range of a mixing ratio of solvents by utilizing a result of thin-layer chromatography.A liquid chromatography method for separating a mixture of two or more kinds of compounds, comprising the following steps: (1) performing thin-layer chromatography or column chromatography in a mixed solvent of two or more kinds of solvents having a different mixing ratio from each other or a single solvent; (2) creating a relational expression between a mixing ratio and an elution degree of a solvent for each compound in a sample based on a result of the step (1); and (3) determining an optimum condition based on the relational expression, and performing liquid chromatography.