The invention relates to a centrifugal tube for micro-extraction of dispersion liquid. An orifice part which has a slender structure is formed in such a manner that a pipe wall extends to an upper end in an inwardly-concave circular arc form; the length of the slender orifice part is between 0.3 and 0.8 centimeters; and the inner diameter of the orifice at a front end is between 1 and 2 millimeters. A method for micro-extraction by using the centrifugal tube comprises the following steps of: adding 10 ml of water sample into the centrifugal tube; adding a solvent into the centrifugal tube and mixing the solvent and the water sample to form mixed solution; sealing the orifice of the centrifugal tube and rotating the orifice at a speed of 4,000 rpm by using equipment, so that the mixed solution is clarified and an extraction solvent floats on the top surface of the mixed solution; adding 1 ml of purified water into the centrifugal tube to lift the extraction solvent at the position of the orifice; and collecting the extraction solvent by using a chromatogram sample needle and putting the collected extraction solvent into a chromatographic apparatus for analyzing. The disadvantage that only a solvent of which the density is higher than that of water can be used in the conventional device for micro-extraction of the dispersion liquid is overcome.