For submarine oil-filled cable, the micro-water content and dielectric strength of insulation oil are important parameters to detect properties. In this paper, to explore variation trends of micro-water content and dielectric strength, the insulation oil of submarine oil-filled cable is pretreated in different ways by the oven, and the micro-water content and the breakdown performance of insulation oil after pretreatment is detected by Karl Fischer method and electrical breakdown theory. The experimental results showed that after comprehensive considering the time cost and electrical breakdown performance of pretreatment, when the pretreatment condition was 120 ℃ and 12 h, the micro-water content of insulation oil decreased by 65.73 % and the dielectric strength of insulation oil increased by 22.92 %. And then when the pretreatment temperature and time of insulation oil were different from the pre-treatment condition of 120 ℃ and 12h, micro-water content of insulation oil increased, or the dielectric strength decreased.

insulation oil, pretreatment condition, micro-water content, electrical breakdown performance