A global daily altimetry data set was recently established at the Naval Research Laboratory on the base of Geosat Follow-On, TOPEX/Poseidon, and ERS-2 data. After quality control such as tidal and orbit error removal, referencing to a consistent mean, it provides a global sea surface height (SSH) data with high temporal and spatial resolutions. We identify the first baroclinic Rossby waves with a phase speed around 3-5 cm/s in the northern South China Sea using 1994-2001 daily SSH data. We also find that there is no evident Rossby wave signal in the southern South China Sea.