The spawning of Sinonovacula constricta can be induced by lowering the temperature ofsea water from about 20℃ to 10℃--1℃ for 1--36 hours and then raising the temperatureto about 20℃. This method gave positive results in efficiency of 15-70.9 per cent. Withinthe limits of these conditions (10--1℃ and 1--36 h.), the lower the temperature ofthe water and the longer the time treated the higher will be the efficiency. The spawning is also dependent on the presence of certain amounts of oxygen in thewater. When the animals are spawning, there are not any motions of the shells.