Abstract: From engineering practice,the paper discusses the flexible antenna pointing control problem in momentum bias system which is widely used.The flexible antenna has large size(diameter from 3m to 5m)and requires high pointing precision(0 05°).After deriving the dynamic equations of the satellite with flexible antenna,and analyzing and improving the study of restraining the vibration caused by the movement of flexible antenna,the paper gives a practical method of antenna pointing control in a three axis stabilized satellite with momentum bias system.Finally,after a close loop digital simulation,the paper summarizes the main factors affecting antenna pointing precision.