Based on chironomid analysis for sediment core T0905 from Meiliang Bay,Lake Taihu,response patterns of chironomid assemblages to lake trophic changes were discussed.Results show that chironomid assemblages experienced a notable community shift from predominant Tanytarsus to Chironomus plumosus-type and Microchironomus dominated at around 1970.Before 1970,chi-ronomid assemblages were dominated by Tanytarsus,which is an indicator of relatively good water quality and moderate trophic sta-tus.Subsequently,the relative abundance of Tanytarsus decreased along with the increase of eutrophic indicators such as Chironomus plumosus-type and Propsilocerus akamusi-type.Especially from 1990,the abundance of Microchironomus tabarui-type had a sharp increase,denoting that Meiliang Bay has already become eutrophic level from meso-eutrophication.