Culture of small abalones, Haliotis diversicolor has expanded quickly due todevelopment of successfully propagation and larviculture. However, in recent years,farmers have experienced mass mortality of abalone reared in the grow-out ponds. Theabalone larvae often can't success to settle in the nursery stage. The bacteria, Vibriospp., have been documented to caused vibriosis leading to death of abalone in warmerwater temperature.Abalone does not possess immunoglobulins. The major roles of defense systems inabalones are hemocytes and humoral systems (lysosomal enzymes, lectin, etc.). When theabalone is challenged with the virus and bacteria, the immune systems will response toface the infection. Herein, we try to find some immunostimulants, which can increasethe defense activity of abalone. We also investigate the effects of immunostimulants onthe immuno responses of stock abalone. Through the maternal effect, we could obtainbetter healthy larval abalone.