Total dissolved chromium, particulate chromium, hexavalent chromium and chromium of aerosols in the Changjang River and its estuarine area have been determined by f1ameless atomic absorption. spectrophotometry. Investigation results indicate that content of total dissolved chromium is below 0.2 μg/L in the lower reaches of the Changjiang River, reaching the highest 1.18 μg/L in the estuary, and between 0.1 and 0.5 μg/L in the estuarine region. Hexavalent chromium is the principal speciation in river water. Trivalent chromium is the dominant speciation in estuarine water. Content of total chromium in Changjiang River and estuary is between 0.98-12.3 μg/L. Ratio of particulate chromium to tota1 chromium is over 80%, major ratio is more than 95%. So particulate chromium in Changjiang River and estuary have been considered the most principal speciation of existing chromium. Under the physical and chemical condition of the estuary, hexavalent chromium in sea water is reduced to trivalent chromium by organic matter, and trivalent chromium is adsorbed by suspended matter, resulting in particulate chromium and transport. of chromium speciation. Chromium content in aerosols also reflected the influence of pollution source, since chromium content in aerosols can affect chromium distribution in surface sea water.