HY 1 (Haiyang = Ocean) is the first operational remote sensing satellite based on the CAST968 bus. The 365 kg box-shaped satellite is three-axis-stabilized and Earth-oriented, with the twin solar wings oriented to the sun. It incorporates an integrated onboard operation management system and has a design life of two years. Its payloads include a 10-band ocean color scanner with a revisit period of 3 days and a 4-band CCD imager with a revisit period of 7 days.

HY-1 can provide real-time observations of China's coastal regions such as the Bohai Sea, the Huanghai Sea, the Donghai Sea, the Naihai Sea, and other seacoast regions. Remote sensing data on the rest of the world can be stored in the onboard data storage device for delayed replay.

The main task of HY-1 is to observe sea optical characteristics, chlorophyll concentration, surface temperature, suspended silt charge, soluble organic matter, and pollution. It can also be used to observe sea ice, shallow sea terrain, ocean current characteristics, and atmospheric aerosol on the sea surface.