Abstract: Plasma membranes were prepared from grand-cover chrysanthmum (Dendranthema×grandiflorum Kitamura) leaves by aqueous polymer two-phase partitioning system which was composed of Dextran T-500 and PEG 3350. The effect of the concentration of polymer and salt on partition of plasma membrane in aqueous polymer system was studied. The results from the electron micrograph staining with phosphotungstic acid and the mark enzyme activity analyses showed that the preparation of the right-side-out plasma membrane vesicles from grand-cover chrysanthmum leaves had obtained high purity and yield by the system which consisted of 6.2%(W/W) Dextran T-500 and PEG 3350, 7 mmol.L-1 NaCl.