To study the effects of cold-havrdening on jasmine seedlings under cold stress,changes of relative conductivity and Malondiadehyde(MDA) content in Single petal jasmine and Double petal jasmine were observed.The results show that cold-havrdening could alleviate effectively the decrease of relative conductivity and MDA content caused by cold stress.The physiology effective phase of cold-havrdening on Single petal jasmine and Double petal jasmine was 2 days and 4 days respectively.