The work aims to study erosion law of seawater pipelines by ice particles under vibration condition, and put forward optimization measures for seawater pipeline system to ensure safe sail in polar region. Discrete phase model, erosion wear model and dynamic grid technology in CFD (computational fluid dynamics) were employed to study erosive wear characteristics of horizontally and vertically arranged 90° elbows by ice crystals under different vibration conditions. Service life variation of the pipelines was predicted. Vibration would change the seriously worn position of the elbows. The effect of vibration on horizontal elbows was greater than that on the vertical elbows. When the amplitude was constant, service life of the vertical elbows was longer than that of the horizontal elbows. Service life of the horizontal elbows decreased from 218.64 days to the minimum, 12.75 days while that of vertical elbows decreased from 332.40 days to 43.12 days. At the amplitude of 1mm and frequency of 10~20 Hz, service time of the horizontal elbows changed abruptly from 112.01 days to 173.24 days, and then reduced significantly. Vibration has significant effects on service life of 90° seawater pipelines. Service life of pipelines subject to 80 Hz, 2 mm vibration is 205.89 days shorter than that of original ones.