The invention discloses a dewatering and demisting device of a rearview mirror of a vehicle. The dewatering and demising device of the rearview mirror of the vehicle is composed of a rear cover, a mirror body, a driven roll, a strip mirror, a supporting plate, a strip mirror scraper, a drive roll, a cleaning roll scraper and a cleaning roll. The dewatering and demising device of the rearview mirror of the vehicle is characterized in that the rearview mirror is composed of the rear cover and the mirror body; the cleaning roll scraper is mounted on the rear cover; the driven roll, the supporting plate, the strip mirror scraper and the drive roll are mounted on the mirror body, and water holes are formed in the lower portion of the mirror body; the strip mirror is mounted on the driven roll and the drive roll; and the drive roll drives the strip mirror to wind across the driven roll to rotate clockwise, the supporting plate adsorbs the strip mirror and slides by attaching to the front side of the supporting plate, the strip mirror scraper is used for scraping off water and mist debris on the mirror surface, the cleaning roll is used for cleaning the strip mirror surface again, the cleaning roll scraper is used for scraping off water on the cleaning roll, and the water flows out of the mirror body water holes. Compared with the prior art, the dewatering and demisting device of the rearview mirror of the vehicle has the beneficial effects that after the dewatering and demisting device of the rearview mirror of the vehicle is started, water or mist can be immediately removed, and the mirror surface is kept clean.