Submerged impinging jets in a plunge pool downstream of large dams are experimentally investigated in details. By use of the hot|film anemometer, the velocity field in the plunge pool produced by middle orifices of 1∶400 scale Xiluodu spillway model is measured. The diffusive characteristics and energy dissipation mechanism of the submerged impinging jet in the plunge pool are analyzed. By use of the hot | film anemometer, the velocity field in the plunge pool produced by middle orifices of 1: 400 scale Xiluodu spillway model is measured. The diffusive characteristics and energy dissipation mechanism of the submerged impinging jet in the plunge pool are analyzed.