Abstract: The impacts of some inducing substances on the settlement and metamorphosis of planktonic larvae of the abalone Haliotis discus hannai were studied. According to the composition of amino acid in 6 monocultured benthic diatom, 15 artif icial synthetic amino acids were chosen as the inducer. The results of the inducing experiments showed that the highest settlement rate appeared in the group with L..aspartic and the second in L.. glutamic test group. These two rates were a little lower than that of benthic diatom test group and much higher than control group. About inducing metamorphosis rate, L..aspartic test group and L..glutamic test group are same. Both are a little higher than benthic diatom test group and are much higher than the control test group. The experiments w ith different concentration of inducing substances indicated that the highest inducing rates occurred when the concentration was 10- 5mol..L- 1for both L..aspartic and L..glutamic acid.