Abstract: An experimental result in the deep sea is presented. The experiment has shown that, under the condition of negative velocity gradient, the turning-point convergence-zones can be form: d by the sound reflected from the sea bottom. For a source-and receiver-depth at 100 in and a frequency at 200 Hz, the gains of the first three convergence-zones are of the order of 13 to 14 dB. Calculated gains and positions are consistent with experimental results.