C7-asphaltenes and the heavy resin fraction (HRe, i.e., the fraction insoluble in n-pentane but soluble in n-heptane) were separated from two typical heavy residues. The role of HRe in asphaltene aggregation was mainly explored. First, the effect of HRe on the size of asphaltene aggregates in heptol solvents was studied by dynamic light scattering. The average aggregate size of asphaltenes upon the increase of the resin concentration shows that HRe could inhibit asphaltene aggregation more efficiently than the light resin fraction (LRe, i.e., the polar fraction from C5-maltenes by adsorption chromatography). However, an obvious size increase of asphaltene aggregates is observed when HRe exceeds some concentration. This can be tentatively attributed to the prior adsorption and penetration of resins in the less polar asphaltenes, followed by the reaggregation of the remaining asphaltenes due to their more aromatic and polar nature. Then the thermodynamics of the asphaltene phase behavior in solutions with the addition of resins were discussed in terms of the molar Gibbs free energy (Delta g) based on the Flory-Huggins polymer theory. HRe is more inclined to act as the dispersed phase and could effectively orient the Delta g of asphaltene solutions. Moreover, adsorption isotherms of resins on asphaltene solids were obtained, and the adsorption equilibrium constant (K-AR) was then calculated. HRe presents a much higher K-AR with asphaltenes than LRe. These results indicate that the more aromatic and polar resin fraction, HRe, could serve as a highly efficient peptizing agent for asphaltene stabilization. Through X-ray diffraction analysis, it is found that the aromatic stacking of asphaltenes can be effectively disrupted by peptization of HRe, thus leading to the increase of the layer distance between aromatic sheets (d(m)) and the average height of the stack of aromatic sheets (L-c) as well as the decrease of the average diameter of the aromatic sheet (L-a).