Abstract: Scaling often has serious influences on the normal production and development in the process of oilfield production. The problem of scaling became severe in the fourth plant of Daqing Oilfield after ASP flooding was applied. The scale does not dissolve in acid or alkali. In order to solve this problem, a high pressure physical model device was applied to simulate the scaling in the field. Based on analysis of the permeability and chemical elements of the core in the scaling reservoir, the reason for scaling was analyzed and expounded comprehensively, thereby providing theoretical basis for descaling and anti-scaling measures.