The invention provides an oil-water separation tank. The oil-water separation tank comprises an oil tank, a condensation coiled pipe, a heating coiled pipe, an emptying valve, a feeding hole, a discharging hole, sight glass and a water shearing opening, wherein the oil tank is divided into three parts, namely a heating region, a condensation region and an observation region; the oil tank is divided into inner and outer layers; the inner layer is a sealed space when the emptying valve, the feeding hole, the discharging hole and the water shearing opening are closed; the condensation coiled pipe is wound in an outer layer cavity at the top end of the oil tank to form a condensation region; the heating coiled pipe is wound in an outer layer cavity at the bottom end of the oil tank to form a heating region; the feeding hole is formed in the upper half part of the right side of the oil tank and the discharging hole is formed in the lower half part of the left side of the oil tank; the water shearing opening is formed in the bottom end of the oil tank; the emptying valve is mounted at the upper half part of the left side of the oil tank; and the surface of the tank wall of the condensation region is coated by a smooth coating so that oil drops can slide off. According to the oil-water separation tank, a simple and efficient method for improving the temperature of liquid is adopted and the density difference of an oil phase and a water phase is changed so that the oil and the water can be rapidly separated, so that the oil-water separation time is shortened, and furthermore, the good separation effect is realized; and most importantly, the problem that the oil and the water cannot be separated in winter is solved, the production efficiency is improved and the loss of crude oil can be reduced, so that the production cost is reduced.