The invention belongs to fields of solar photothermal conversion, sea water desalinization and new materials and relates to a solar photothermal purification method of water based on corncob integralcarbon material. According to the principle, the natural structural feature of corncob is utilized, the corncob is carbonized at a certain temperature but not powdered, and the integral corncob-basedcarbon material is prepared and is utilized to perform solar photothermal evaporation of water; part of the corncob integral carbon material is vertically soaked in water to be purified, and the otherpart is vertically exposed in air; clean water is produced with water vapor under sunlight irradiation. The method herein is suitable for purifying water, including sea water, bitter salty water, high-fluorine water, industrial wastewater, domestic wastewater and the like. Agricultural product wastes and renewable clean energy, solar energy, are utilized herein to produce clean fresh water; the method herein is simple and efficient, low in carbon, green and free of pollution; the water purification method is provided herein.