Abstract: The multiphase transportation represented by water-waxy crude oil is a universal storage and transportation process used for oil gathering and production of oilfields. In the background of surface process optimization and energy saving & efficiency increasing development, the flow assurance in the process of multiphase transportation gets more complex and severe due to the effect of oil-water emulsification mechanism. In this paper, the method for characterizing the morphology and aggregation behavior of wax crystal in the oil-water emulsification system was developed by combining the polarized optical microscopy experiment and the ordinary light microscopy experiment together. By virtue of this method, the microscopic morphology and aggregation structure characteristics of wax crystals with emulsified water were presented intuitively and the distribution laws of the characteristic parameters of wax crystals under the effect of emulsification mechanism were quantified. It is indicated that with the increasing of temperature and emulsion shear action, the morphology and structure of wax crystals tend to regularization and the aggregation behavior is inhibited. The effect of water content on the morphology and aggregation behavior of wax crystals in oil-water emulsification system is presented as a feature transformation near the phase inversion point. The quantitative characterization and analysis on the morphology and aggregation behavior of wax crystals in the environment of emulsification provide necessary foundation and beneficial basis for further understanding on the mechanism in the wax deposition process of water-waxy crude oil two-phase flow in the shear flow field of pipeline transportation.