Abstract: The characteristics of produced liquid by ASP flooding process include high wax content, high viscosity, serious emulsification and great amount of mechanical admixtures and clay particles. With temperature decreasing during the transportation process in oil gathering pipeline, these materials may be continuously precipitated, thus causing serious deposition problem to surface oil gathering system. In this paper, the composition and deposition regulation of precipitated materials in oil gathering pipelines of Daqing oilfield are studied bylab experiments. The results show that the precipitated material is black and viscous mixture mainly composed of wax. And the influencing factors are polymer concentration, oil gathering temperature, water cut and flow velocity, etc. The precipitating velocity increases with the increasing of polymer concentration and decreases with the increasing of oil gathering temperature, water cut and flow velocity. This study provides the theoretical foundations to take preventive and control measures for forming precipitated materials in oil gathering pipeline by ASP flooding process. It is of important significance for insuring the safe production and operation in oil gathering pipeline