[Purposes] The wax content has a great influence on the pavement performance of asphalt, and it is very important to accurately measure and limit the wax content. Commonly used test methods for wax content have problems such as large errors and complex procedures, and it is difficult to reveal the essence of wax crystallization. To solve issue, this paper constructed a prediction model of wax crystallization in asphalt from a theoretical point of view. [Methods] Taking two kinds of asphalts from SHRP （strategic highway research program） as the research objects, the asphalt was regarded as a solid-liquid two-phase system, and a wax precipitation model was constructed based on the phase equilibrium theory and the normal solution model. [Findings] A parameter of a was used to consider the branching effect of the melting heat for n-alkanes, and a parameter of c was used to consider the influence of aromatic content. When the parameter a was 0.3 and c was 0.6, the wax precipitation temperature (wax precipitation temperature, WPT) and wax precipitation curve predicted by the model （wax precipitation curve ，WPC) was generally consistent with the test results. A higher carbon number and content of n-alkanes resulted in, more obvious wax precipitation. The increase in aromatic content can lead to an increase in wax precipitation temperature.[Conclusions] By categorizing asphalt components into P (normal alkanes), N (isoalkanes), and A (aromatics), it is feasible to construct a wax content prediction model based on thermodynamics and regular solution theory. Calculations of thermodynamic parameters such as melting point, enthalpy of fusion, and solubility have a substantial influence on the predictive results. The compatibility between normal alkanes and aromatics affects asphalt component interaction, thus exerting an impact on wax precipitation.