induced by inhibiting polar body (PB2) releasing with hypotonic treatment. Different hypotonic treatments, including salinity (4, 6, 8, 10, 12, 14 and 16), initial treatment time (at the time when the first PB1, 30 percents of PB1, 40 percents of PB1, 50 percents of PB1 and the first PB2 were observed) and duration time (10, 15, 20 and 25 min) were tested at 23 water temperature. (89.16±1.39) when the fertilized eggs were treated for 15 min with hypotonic solution with salinity of 8 at the time when 40triploids werediploids. And triploid larvae appeared much superiority in growth.hypotonic treatment,cold shock (2 The triploids by cold shock, heat shock and 6-DMAP, and the difference in hatching success and D-larval size was significant 0.056-DMAP treatment was higher than that by hypotonic0.05) of hypotonic treatment is superior over those of other three triploid induction treatments. Because of the low price, the high induction ratio of triploids and security, it is feasible and worthwhile to induce