As the initial stage of crystallization, nucleation directly affects the structure, chirality, purity, crystal forms and particle size distribution of crystal products. However, due to the random nature of nucleation, experimental methods are not only time-consuming and laborious, but also difficult to understand the molecular interactions. In this paper, ethyl paraben (EP), propyl paraben (PP) and butyl paraben (BP) with similar structure were selected as model substances, and the binding energies of single solute and single solvent molecules of EP, PP and BP in four different organic solvents (ethanol, ethyl acetate, acetone, acetonitrile) were calculated. The interaction of EP, PP and BP with each solvent decreases in the following order: ethanol>ethyl acetate>acetone>acetonitrile. Therefore, it can be predicted that EP, PP and BP nucleate slowest in ethanol, slower in ethyl acetate and acetone, and fastest in acetonitrile. When the solvent is the same, EP is the most difficult to nucleate, followed by PP, and BP is easy to nucleate. The predicted results are consistent with the experimental results. This study proves that the solute-solvent (1∶1) model can predict the difficulty of nucleation, which is conducive to solvent screening and improve experimental efficiency.