Abstract: In allusion to the poor property of crude, the flocculation of asphaltene and the subsequent problems in the procedure of crude oil exploiting, storage and process, the colloidal property of crude oil is reviewed from the colloidal model, the colloidal particle size and the colloidal stability. Since the petroleum colloidal theory was put into forward, researchers have test verified the small angle x-ray scattering and small-angle neutron scattering (SANS), and have established a number of colloid models with different dispersed phases and mediums. Characterization approaches for the stability of colloid includes droplet diffusion, optical instrument law, acoustic resonance method, viscometric method and conductivity method. The main factors influencing the colloidal stability are colloidal volume, shape and particle size; amounts of asphaltenes and its chemical structure, and the chemical structure of additives. The methods to test the size of colloidal particle of asphaltene are divided into 3 kinds, that is, dynamic light scattering, parameters method of fluid mechanics and photoelectric microscopic analysis. It is considered that proper application of additives can effectively deal with the flocculation and deposition of asphaltene to improve the utilization rate of oil resource.