It is widely accepted that colloids play an important role in the contaminant migration process at present. However, the colloid deposition structure on rock surfaces has scarcely been studied. In this paper, preliminary results for a fractal characterization for colloid deposition in saturated fractures are presented, which consider the pH value, ionic strength, and flow rate of the solution. Under different chemical conditions, deposition behavior obviously changed, and fractal analysis appears to be an effective tool to capture the evolution and general behavior of depositions. Scanning Electron Microscopy (SEM) is used to observe the colloidal growth on granite surfaces and to acquire the visual image on a detailed level. The images are analyzed for their mass fractal dimensions. The influence on colloid fractal deposition is discussed.