Research conclusions: As the water reduction engineering is strong in speciality and obvious in territoriality, the similar experience is very important. For the water reduction in loess sand stratum, the reasonable scheme for the water reduction should be chosen after making the comparisons in economics and technology according to the engineering geological features, the shape and the size of the foundation pit and the experience of the similar work. In the course of implementing the scheme, the effect of the water reduction should be monitored to analyze and optimize the scheme timely and take more effective measures. For the small foundation pit in Xi＇an loess area, the deep well and pipe outside of the foundation pit are used for the water reduction when the width of the foundation pit is less than 20 m. When the width of the foundation pit is more than 20 m, the wells and pipes inside and outside of the foundation pit should be used for the water reduction.