Abstract: The overall analysis and study on transportation process for Zhongning—Yinchuan Oil Pipeline operated in winter are made.The pressure fluctuation before and after the heaters put into operation is described with the collected pipeline operation data and relative calculations.The analysis on the reason of variation in equivalent thickness of wax deposit on pipe wall is carried out.It is pointed out that the problem of pressure fluctuation between No.2 Station and Yinchuan pipe section is successfully solved after heaters put into use, which effectively elongate the pigging period.However, wax deposit occurs in two pipe sections of the whole line, resulting in difficulty in wax pigging.Therefore, a suggestion to equip pig trap in No.2 Station is given.