The invention relates to fully refined edible vegetable oil with lower trans fatty acid and a refining method thereof. The vegetable oil is rapeseed oil, soybean oil, corn oil or blending oil with any ratio; the trans fatty acid content of the vegetable oil is less than or equal to 1 weight percent; and the oil smoke point is more than or equal to 210 DEG C. The refining method comprises the steps of selecting crude oil, degumming, deacidifying, removing saponin, dehydrating, decoloring, removing impurities, deoxidizing, deodorizing, cooling and obtaining finished products. The refining method is characterized in that: at the decoloring state, the removing grain size of the impurities is reduced from 25 mu m to 10 mu m; and at the deodorizing stage, the deodorizing temperature is controlled to be between 230 and 245 DEG C and the vacuum degree is controlled to be within 2 tau. Oil is refined at lower temperature and a lowest trans fat structure is realized by controlling the grain size of the impurities and the vacuum degree; after being refined, the vegetable oil has good quality, namely the trans fatty acid is reduced to be lower than 60 percent of the normal level; and the refined vegetable oil has light color, high smoke point, high purity and storage resistance and is beneficial to people's long-term health.