Abstract: To establish a dynamic modulus prediction-model of asphalt mixtures indicating properties of inclusions and characteristics of microstructure, a three phases micromechanics model to predict dynamic modulus of asphalt mixtures is developed, based on the micromechanics theory of composite. Asphalt mixtures is regarded as a composite by embedding the mastic (asphalt binder) coated aggregate particles into the equivalent medium of asphalt mixtures, and the effect of aggregate size, aggregate gradation and air void distribution are taken into account in this model. The dynamic modulus of asphalt mixtures is then predicted with the newly developed micromechanics model using the studies on properties of inclusions. Laboratory test results show that the predicted dynamic modulus is smaller than measured dynamic modulus. The reasons for the discrepancy between the measured and predicted results might be attributed to the distinction between the assumption of the prediction model and rigorous micromechanical structure. The prediction model is modified by the given analysis, and then a micromechanics methods considering asphalt film thickness is proposed. Whereas the difference of mechanical properties between aggregate and mastic, the solution parameters of the prediction model is simplified, furthermore the range of the parameters value is presented.