According to the present situation and existing technical problems of groundwater monitoring in China, the well building test for 50mm PVC-U tube for nested monitoring well was carried out. Design and construction were implemented for a five-layer nested monitoring well. The paper introduces the overall structural design, PVC-U well pipe, new type of clay balls for water stop, centralizer, key technology of well completion and the final results of the monitoring well. This work can offer a reference for the construction of multi-layer nested monitoring wells and provide support to the development of groundwater multi-layer monitoring well technology in China.