In the asphalt industry, interaction between crumb rubber modifier (CRM) and asphalt is conducted at different interaction conditions, which leads to various mechanisms of interactions and consequently different physical properties of final product. Several studies explained different mechanisms of interaction at macro level (changes in CRM particle size and morphology) and the exchange of components between CRM and asphalt. In this study, we are investigating the mechanism of interaction between the CRM and asphalt at molecular level using analytical techniques such as gel permeation chromatography (GPC) in combination with thermo-gravimetric analysis (TGA). The TGA shows the type of the material being released from CRM particles into the asphalt matrix. The GPC shows that the components of CRM released at certain mixing temperature (i.e. 190°C) have higher molecular weight than the ones released at higher mixing temperature (i.e. 220°C). Also, temperature sweep viscoelastic analysis on the CRM binder and its extracted liquid phase (CRM removed) indicates that the released components with high molecular weights are able to create internal network structure in the asphalt and consequently enhance its mechanical performance.