FengYun-3B (FY-3B), the second experimental satellite in the second generation of the Chinese polar-orbiting meteorological satellites, was launched at Taiyuan, China, launching center on 5 November 2010. Equipped with both imaging and sounding payloads, as the afternoon orbit satellite, enabling more powerful observations combining with the morning orbit satellite FY-3A, FY-3B carries 11 optical and microwave instruments same with FY-3A. The instruments spectral bands cover ultroviolet, visible, near-infrared, infrared, and microwave spectral regions, are very similar with FY-3A. FY-3B instruments can be used to detect and investigate weather, clouds, radiation, climate, atmosphere, land, ocean, and other environmental features. FY-3B In-Orbit Checkout(IOC) took about 4 months following its launch; FY-3B has been operational, and provides remote sensing data to user since March 2011. The future operational satellites of FY-3 series is to operate two polar-orbiting spacecraft—one in the morning and the other in the afternoon orbit—with different payloads for each spacecraft. This orbit configuration will be further coordinated with the World Meteorological Organization (WMO). One low-inclination orbit spacecraft is under consideration for rain-radar and passive microwave precipitation measurement missions. An overview of the FY-3B , and its imaging and sounding capabilities and potential applications are given in this paper.