With the advancement of oilfield extraction technology, since oil-water emulsions in waxy crude oil are prone to be deposited on the pipe wall, increasing the difficulty of crude oil extraction. In this paper, the mesoscopic dissipative particle dynamics method is used to study the mechanism of the crystallization and deposition adsorbed on the wall. The results show that in the absence of water molecules, the paraffin molecules near the substrate are deposited on the metallic surface with a horizontal morphology, while the paraffin molecules close to the fluid side are arranged in a vertical column morphology. In the emulsified system, more water molecules will be absorbed on the metallic substrate than paraffin molecules, which obstructed the direct interaction between paraffin molecules and solid surface. Therefore, the addition of water molecules hinders the crystallization of wax near the substrate. Perversely, on the fluid side, water molecules promote the formation of paraffin crystallization. The research in this paper reveals the crystallization mechanism of paraffin wax in oil-water emulsions in the pipeline from the microscopic scale, which provides theoretical support for improving the recovery of wax-containing crude oil and enhancing the transport efficiency.