Great and differential settlement occurs under the building during an adjacent metro deep foundation pit construction. Factors influencing the building settlement in different construction stages are analyzed based on the monitoring data and geology distribution condition. The result shows that the large lateral deformation of retaining wall and time-depended deformation of soft clay under the building are the reasons that make the major settlement occur.The main factor inducing differential settlement of the building is local distribution of adverse geological condition. Some feasible means of improvements in practice are presented, which can reduce effectively the influence of adverse geological condition such as buried channel on excavation and surroundings. Though the paper the author hopes that engineers can attach more importance to the negative influence of adverse geological condition, and the results could be valuable reference to other engineering.