During the wintertime monsoon, a tongue-shaped thermohaline front is established at the Yellow Sea entrance. The frontal circulation as well as the frontal structure has been investigated by analyzing conductivity-temperature-density data, float tracks, current data, and wind data. The northern part of the tongue-shaped front displays a wave-like motion of 20 km in amplitude and 80 km in wavelength and isotherms, isohalines, and isopycnals are downward declined toward the north. The geostrophic current field indicates formation of a cyclonic circulation along the front which consists of a westward transversal current along 34° N and a southeastward outflow along the 50-m isobath of the Changjiang Banks. The float experiments evidences not only the existence of the transversal current, but also the cyclonic frontal circulation. The new observational findings do not match the classical paradigm of a northerly wind-driven circulation.ta, float tracks, current data, and wind data. The northern part of the tongue-shaped front displays a wave-like motion of 20 km in amplitude and 80 km in wavelength and isotherms, isohalines, and isopycnals are downward declined toward the north. The geostrophic current field indicates formation of a cyclonic circulation along the front which consists of a westward transversal current along 34° N and a southeastward outflow along the 50-m isobath of the Changjiang Banks. The float experiments evidences not only the existence of the transversal current, but also the cyclonic frontal circulation. The new observational findings do not match the classical paradigm of a northerly wind-driven circulation.