The climatic impact of the Eldgjá eruption happened in about 934AD in China was investigatedThe relevant historical data，mainly Chinese historical data，as well as the tree ring records were searched and sortedBased on the Chinese，Japanese and European historical records，as well as the tree ring records，we found that climatic cooling occurred at about 934～935AD and 939～942AD following the Eldgjá eruption The cooling of 934～935AD seemed to be regional and limited to Europe and the Middle East，and that of 939～942AD would probably be globalFollowing the Eldgjá eruption until 938AD，regional warming appeared in China with its climax in 934ADNotable cooling appeared in 939～942AD in China By a tentative estimation，the cooling magnitude would be 5～8℃ in the winter of 939/940AD in comparison with the mean winter temperature of 933～938AD in Luoyang Kaifeng area Our investigation supported that the ～934AD Eldgjá eruption would have two climaxes，iethose in about 934AD and 939AD respectively