The oil fluid containing water is treated by specific YII turbine oil filter to remove its water in order to restore its performance. The contrast experiments are conducted on the factors affecting the dewatering efficiency of a vacuum filter such as temperature, vacuum degree, treatment time, ventilation amount, and ventilation position, and the optimal dewatering efficiency is obtained under the condition of 60 ℃, 19L/min lower portion aeration and 0.090Mpa vacuum degree after the analysis of the changing trends and reasons of dewatering efficiency under each treatment condition.