Abstract: This paper introduces the configuration,characteristics and system design of the antenna subsystem,which meets relevant requirements of the Command and Data Acquisition Station (CADS) of FY2 China′s first geostationary meteorological satellite.CDAS antenna subsystem mainly consist of antenna mechanical Structure,feed network,antenna control unit (ACU) and monitoredcontrol (MAC).This antenna is a 20m modified cassegrain antenna,its feed is a corrugated horn,and adopts multiplemoulding autotrack monopulse method.The servo position loop consists of the angle encoder.Antenna is driven by 3phase SCR and servoDC motor.The backlash is eliminated by using dualmotor.ACU has multipleoperation modes and is easy controlled.ACU monitors working parameters and status of system,and detects the errors online.