Abstract: A long-span complex steel grid structure was monitored closely during the construction process,including stress change monitoring for sensitive and important steel components in hoisting procedure,and supporting point deformation monitoring for demolishment of temporary support structure,and welding ring deformation monitoring for ascent of the whole welding ball.Monitoring results demonstrated that stress and deformation were in reasonable range,and eventually stabilized to a value,and the monitoring effect was fine.The steel grid structure was conducted with finite element simulation analysis on stress and deformation of various working conditions during construction course.The measured stress and deformation values were compared with those of finite element analysis,and substantial agreement was obtained,which demonstrated that finite element analysis simulated the change of stress and deformation in construction process satisfactorily.