The reaeration performance in smooth and parallel flashboard spillways with 3cm, 6cm and 9cm board space over curve dams has been experimentally investigated respectively. Reaeration efficiencies of different types of spillways, in particular the effects of varying discharge rate of overflow and drop-water depth have been taken account in detail. The test data illustrates that the reaeration efficiency increases with increasing drop-water depth, and decreases with increasing discharge current; the flashboard spillways appear to offer markedly higher reaeration efficiency than the smooth spillway, which increases gradually with reduction of the space between streamwise adjacent flashboards. Empirical correlations predicting spill Froude number Fdo, relative weir depth hw/h and reaeration efficiency of different types of spillways on curve dams are developed. The results indicate that flashboard spillways are effective for oxygen transfer.