Foundation pit engineering is an indispensable part of building construction. It mainly includes earthwork excavation, water stopping, drainage and foundation pit detection of foundation pit support. In order to ensure the safety of the buildings around the foundation pit and avoid damage after excavation, it is necessary for us to do a lot of investigation before excavation, and to be familiar with the surrounding environment and facilities. In a word, the foundation pit engineering is a comprehensive design problem. Foundation pit engineering has strict regional requirements, although it is the same kind of building, but because of the different environment, there will be great differences in design. For example, when the geological conditions are poor and there are more buildings around, it is necessary to make strict requirements on the excavation and support methods of foundation pit. But if the geological conditions are good, the standard can be lowered appropriately. So the foundation pit design will choose the appropriate construction method because of different engineering conditions.