Triploid was induced by hydrostatic pressure in Pseudosciaena crocea. Pressure shock of 500kg?cm -2 was administered to eggs for 2 min at 3 min after fertilization. The triploid rate was 92. 1 %. The nucleus diameters (major axes) and volumes of erythrocytes in triploid were measured respectively 1. 28 and 1. 70 times those in diploid. The triploid growth rates (body length , weight) were not significantly different compared to the diploid controls. The gonadal development was studied through tissue section. The result showed that the triploids had undeveloped gonads and were sterile.