Characteristics of embryo and Z_1 of Eriocheir sinensis females from 1~(st) and 2~(nd) brood have been investigated.Egg size,wet weight and dry material weight of every embryo in the 1~(st) brood are significantly higher than those of the 2~(nd)(P<0.05).There are no significant difference in water content between the two embryos(P>0.05).The water content of the two embryos increased as the embryos developed(P<0.05).Total lipid decreased gradually as the embryo developed,but only during the 2~(nd) time,it decreases obviously(P<0.05).Z_1 size,total lipid,CMI and PNR_(50) of the two times are significantly different(P<0.05).It indicates that the quality of Z_1 in 2~(nd) brood is not up to that of the first.