With the development of oil and gas progressing from onshore to offshore deepwater, subsea pipeline transportation has become the main mode of transportation in offshore oil and gas production. Due to the low temperature in deepwater, wax deposition is an unavoidable technical issue in oil and gas transportation. The wax deposition of a subsea pipeline in the South China Sea was predicted and simulated using multiphase transient simulation software LedaFlow. The variations of wax deposition thickness, pipeline temperature, fluid temperature and wax content in different years were obtained. According to the simulation results, the wax deposition rule in the subsea pipeline is analyzed, to develop suggestions for the paraffin removal and pigging operation in the future, and providing reference for good engineering practice on this subject.