The influence of crown beam on the deformation of retaining structure of cantilever row piles under different conditions is analyzed by means of combination of numerical analysis and field monitoring.The results show that crown beam can improve the deformation restraint of cantilever row pile retaining structure significantly.With the increase of excavation depth of foundation pit,the restraint effect of crown beam becomes more and more significant.When excavation reaches a certain depth,the deformation of enclosure structure must be controlled by setting crown and beam.After the setting of crown beam restraint,the deformation of retaining structure is more sensitive to the shape change foundation pit,and the restraint effect of crown beam is more significant in arc foundation pit.