In order to evaluate the strength and rigidity of the tower crane rotary platform，based on the finite element plate and shell theory， the finite element model of the upper andlower support of the slewing platform was established.The contact relationship betweenthe slewing bearing ball and the raceway was neglected.The slewing bearing ball was re-placed by the solid cross short column， and the slewing bearing was approximated.The sle-wing platform model test was carried out to verify the accuracy of finite element analysis pa-rameter setting.The results show that the stress of the rotating platform is less than the al-low able stress under dangerous conditions， and the whole structure is safe and reliable.Thestress of the weld between the casing and the ribs increases with the installation angle of theribs.The stress state of the platform has no obvious influence； the finite element results a-gree well with the experimental test data， which verifies the feasibility of finite element a-nalysis.