Abstract: The influence of V_c on membrane fluidity was studied in this artical, by using TEMPO and fatty acid nitroxide spin labeling liposome as -well as normal and malignant cell membrane of mouse liver, in order to explore the anti-cancer mechanism of V_c. The experiments show that V_c can influence the movement of membrane lipids and membrane proteins, increase the fluidity of malignant cell membrane, and the velocity of effect is speeded up with increasing V_c concentration. However, V_c has no evident influence on normal liver cell membrane's fltiidity.In addition, within the studied concen-ration limits,the ability of V_c passing through membrane is obviously different between the normal and malignant cell of mouse liver.