For the deep foundation pit construction in settlement micro-disturbance control area, the horizontal waterproof curtain technique is more and more important in the groundwater control. The design principle of non-pressure groundwater control technology by the horizontal waterproof curtain is discussed and this technology is applied in the groundwater control design of a subway station. The pumping test and the final engineering practice result show that the design and construction of horizontal waterproof curtain have achieved the expected effects. On this basis, the suggestions are put forward for the construction technology & leakage detection methods of horizontal waterproof curtain and the real-time observation & early warning during excavation.