We collected wild Sepia lycidas to cultivate indoors,and observed the embryonic development by using microscopic imaging system.The results showed that the oosperm was milky,translucent,oval,papillary,and one end of the oosperm which was cylindrical ring shaped trapped to the spawning substrate,such as grape-like gathered together regularly.The length of the primiparous oosperm was(39.7?1.7)mm in long diameter and(17.1?1.1)mm in short diameter,the weight was(4.3?0.2)g.The embryo was oval shaped with long diameter of(8.85?0.41)mm and short diameter of(7.74?0.54)mm.When the water temperature was 27 ℃,salinity was 30,the oosperm became the smallest with long diameter of(27.2?0.6)mm and short diameter of(13.3?0.6)mm,and weight was(2.02?0.02)g on the 10th day.After 11 days,the oosperm began to expand.Before hatching,the oosperm became larger with long diameter of(32.7?0.8)mm and short diameter of(19.3?0.6)mm,and weight was(4.68?0.02)g.The embryonic development was compartmentalized into 11 periods,such as oosperm,cleavage,blastula,gastrula,the occurrence of embryonic primodium,the formation of organization,red bead stage,occurrence of heartbeat,pigment appearance,endoskeleton formation stage,hatching.The embryonic development lasted 20 days,the length and width of mantle and weight of hatchling larva were(8.1?0.2)mm,(6.1?0.2)mm and(0.18?0.02)g,respectively.