Abstract: The periodical oscillation and exchange between gasoline and alcohol are explored. It is found from experiment that periodical oscillation can be generated between gasoline and alcohol, and obvious stratification is found in both inner and outer containers. We get the experimental conclusion that oscillation cycle time is proportional to the length of capillary and inversely proportional to the inner diameter of capillary to the power of 4（ T L1/d4）. However, the initial level of alcohol in inner container almost does not affect the oscillation cycle time. We also explore the relation between the change of the level of alcohol in inner container and the change of the length of Capillary and cycle order. Finally, the expression for the change of the level of alcohol in inner container between two unstable equilibrium points is given.

Key words: periodical oscillation, exchange, oscillation cycle time, oscillation between the gasoline and alcohol, stratification