Abstract: The planar laser induced fluorescence（PLIF）approach is used to quantify the exchange flux of the floating system under wave. The floating compartments model are designed with different open exchange areas and the experiments are performed under different temperature differences,and also different wave heights. Under wave condition,the experimental results show that the retention time depends on the wave height（hw）and open area（ A）. The influence of wave height is formed to be most significant,and the temperature is the second while the open area is the least.