Combined with the construction example of Baijiatuan monitoring well of Beijing seismic station, the paper introduced a set of construction technical method which is suitable for boreholes with special requirements in complicated formations, such as unconsolidated layers, cracks and karst caves. The study was made on borehole design, drilling methods, drilling tool gradation selection, wall protection and leakage plugging technologies. Based on the previous drilling experience, drilling technical measures and drilling construction quality control measures for complicated formations were put forward, which can be useful reference for subsequent similar drilling construction.