The invention relates to a system and method for removing disulfide from regeneration exhaust gas of caustic fluid used in liquid gas sweetening process. The system comprises a water-washing tank, a membrane separator and an oxidation tank, wherein the top and bottom of the inner wall of the water-washing tank are separately provided with a water-washing tank demister and a water-washing tank gasdistributing plate which are fixed through bolts; the top of the water-washing tank is connected with the bottom of the membrane separator through a gas discharge pipe; the inside of the membrane separator is provided with a microporous membrane internal part and a coalescence plate which are fixed through bolts; the top of the membrane separator is connected with the oxidation tank through another gas discharge pipe; and the top and bottom of the inner wall of the oxidation tank are separately provided with an oxidation tank demister and an oxidation tank gas distributing plate. The realization method of the invention involves the microbubble water-washing technology, the microporous membrane separation technology and the sulphide oxidation technology. The beneficial effects of the system and method of the invention are as follows: no power is consumed, the recycled disulfide can be used as the chemical raw material, the desulfurization efficiency is high, the cost for treating the exhaust gas is low, and the system and method are environmentally friendly and economical.