Steam flooding can enhance the heavy oil recovery obviously. However, a single steam flooding can not achieve good heavy oil development efficiency by the gravity overlap and steam channeling due to the Gudao viscous heavy oil with respect to interface properties of crude oil and rock wettability. Addition of oil displacement agent in the process of steam drive can obviously improve the recovery efficiency. Excessive addition of oil displacement agent can easily cause formation plugging and increase the production difficulty. With the PVP as the displacement agent, this paper has studied the variation of colloidal stability, structural composition and recombinant sub-particles size of Gudao viscous crude oil reacted by chemical auxiliary steam drive. The results show that it can improve the recovery factor under the action of PVP auxiliary steam-heavy oil reservoir; when increasing the amount of displacement agent, the oil’s starting point of coagulation of asphaltene decreases, colloidal stability becomes worse, and the molecular weight of asphaltene increases; with the increase of the temperature, the oil’s starting point of coagulation of asphaltene decreases, colloidal stability becomes worse, asphaltene content increases gently, the ratio of resin and asphaltene of oil sample decreases, and the molecular weight of asphaltene increases.