Abstract:Under the artificial breeding conditions, the embryogenesis and juvenile development of Solen grandis were observed by light microscopy. The results indicated that the embryonic and larval development of S. grandis included the following stages: zygote, embryo cleavage, blastula, gastrula, trochosphere, d-larvae, and finally juvenile. After 20-24 hours of fertilization, D-larvae appeared at the average daily water temperature of 22.4℃. It took 5-7 days to develop to juvenile, and the juvenile became the adult shellfish after 38 days when the shell length-width ratio was 2.60. The accumulated temperature from zygote to attachment was 3 088.79-5 005.19℃ ·h. After juvenile developed outlet pipe, its intake pipe appeared, and at last the two pipes transformed into one pipe with diplopore. The regression equation of shell length and shell height was y=150.37e0.002 7x,x: shell height (μm), y: shell length (μm), R2=0.985 5, P<0.01. The regression equation of shell length and day old was y=143.38e0.091 6x,x: day old (d), y: shell length (μm),R2=0.979 5,P<0.01. The regression equation of shell height and day old was y=33.979 x-15.450,x: day old (d), y: shell height (μm), R2=0.987 3,P<0.01.