The invention relates to a method for improving computed tomography (CT) measured fluid saturation precision. The method comprises the following steps of: a, performing CT scanning on a dry core sample inside and outside a core holder respectively to acquire CT values; b, performing CT scanning on a core of complete saturated brine inside and outside the core holder respectively to acquire CT values; c, making bound water by using the core in the holder, measuring the CT value of the core in a bound water state, and calculating the saturation of the bound water according to the water or liquid outlet volume after the bound water is made completely; d, performing CT scanning on brine for saturation, oil for experiments and peripheral air respectively to acquire CT values, wherein the CT value of the air is a constant value in any medium; e, calculating the CT value of the brine and the CT value of the oil in the core holder by using formulas III and V; and f, calculating the oily watersaturation in the displacement process by using the formula V according to the corrected brine and oil CT values acquired in the step e, wherein the relative error of the saturation is within 1 percent.