The article describes the research of the oil asphaltene phase behavior in the model system and in oil by means of the photon correlation spectroscopy. It distinguishes the system transition from molecular to colloidal-dispersed state with the changing of asphaltene concentration in the model system. The aggregation modes of oil asphaltenes in the model system were defined. There were evaluated the characteristic diffusion time and characteristic interaction time for the aggregation modes, along with the aggregative and sedimentation stability of the systems. There were also presented the dependence of characteristic interaction time of the amount of n-heptane added in the model system. The particles of asphaltene, resin, and paraffin materials were discovered in the crude oil. There was held the comparative analysis of asphaltene aggregation process in oil and model system. There was also got the dependence of the initial fixed radius of the particles of asphaltene, resin, and paraffin materials from the amount of n-heptane, added in oil.