Eggs of Trionyx sinensis were incubated in arenaceous substrate with the diameter of sand granule 0.3-0.6 mm and the humidity 7%-10%.The temperature incubated was 33.0±0.5℃ and the relative humidity was 70%-85%.The incubated period was 35-36 d.Embryos of different developmental stage were taken out through breaking up eggshells.Slices were made in order to observe morphological and histological characteristics of the eye development of T.sinensis.Protuberances of eye vesicle appeared on tow sides of the head on 4th day after incubated.The pigment began to appear in eyes on the 6th day.On the 14th day,brown pigment became black.On the 7th day,the pupil appeared.The crystalline lens was visible through the pupil.The iris appeared on the 14th day.It became actinomorphic around the pupil in the 18th and 19th day.The scleral stalk was appeared on the 19th day,increased to the maximum on the 21st day and disappeared on the 23rd day.The upper eyelid and the lower eyelid appeared on the 19th day and the 22nd day respectively.The eyelid was able to cover the pupil on 32nd day,and the eye was similar to mature eye in the form.The cutis ectoderm formed the cornea primordial and the lens vesicle after the 3rd day.After the 32nd day,the cornea developed completely.The crystalline lens developed completely after the 34th day.The nerve ectoderm differentiated and formed the optic vesicle on tow sides of the forebrain from the 44th to 48th hour.The optic cup,which was differentiated from the optic vesicle,gradually differentiated and formed the retina.8-stratum structure of the retina was basically formed after the 23rd day.The retina developed completely after the 34th day.