Advanced microwave atmospheric sounder (AMAS) is the new generation of microwave humidity sounder onboard FY-3(C/D) satellite, and is inheritance and development of MWHS onboard FY-3(A/B) satellite. Based on 150 GHz (horizontal and vertical polarization) and 183.31 GHz (horizontal polarization, three-channel) of MWHS, the AMAS still operated in cross-orbited scanning and used for deriving atmospheric temperature and humidity of the vertical distribution, rainfall, etc. The observation channels are advanced as 89 GHz (vertical polarization), 118.75 GHz (horizontal polarization, eight-channel), 150 GHz (vertical polarization), 183.31 GHz (horizontal polarization, five-channel).This paper mainly introduces the design and structure of AMAS and describes its performance requirements. Test results show that the performance indicators of AMAS meet the design requirements.