Abstract: After freezing rain and snow disaster in 2008,four fixed sample plots (P1、P2、P3 and P4)were selected to measure the effects on the plant diversity of the subtropical evergreen broad-leaved forest in Chongyi County from 2008 to 2012.The result showed that Pinus massoniana,Alniphyllum fortunei and Alnus cremastogyne disappeared,and Elaeocarpus decipiens appeared.The important value of tree species which ranked the first before freezing rain and snow disaster was reduced.These tree species included Oachestnut,castanopsis fargesii,and Schima superba.The important value of Choerospondias axillaris increased within five years after the freezing rain and snow disaster.P1and P2 increased,P4 reduced,P3 changed little for the Margalef index of the arbor layer.P1 increased,P2 and P3 changed little,P4 reduced for the Shannon-wiener index of the arbor layer.P1 increased,P2 and P3 basically unchanged,P4 reduced for the Pielou index of the arbor layer.The species kinds and the species number increased or reduced under forest,and species increasing inluded Adinandra millettii,vine plants and Mallotusapelta Muell,and disappearing species included Buxus sinica,Dendranthema lavandulifolium,and Pleioblastus amarus.The quantity of Dicranopteris linearis and Cymbopogon citratus increased much.From the beginning of 2011,the canopy density of forest recovered to the level before freezing rain and snow disaster.

Key words: freezing rain and snow disaster, plant diversity, subtropical eevergreen broad-leaved forest