The spotted babylon (Babylonia aerolata) is one of the highest value marine gastropods in Taiwan. In resent years, the heavy exploitation of spotted babylon has resulted in a rapid decrease in its natural resources. Therefore, in order to develop a technique for mass seed production, four treatments of different substrata including sand, sand with fragmental coral, fragmental coral and control groups were designed to evaluate the efforts on the spawning of this species. The results showed that there were no significant difference among the three-experimental groups. However, they were significantly more effective than in the control group.The fertilized eggs, enveloped in sun-flower-seed-shape capsule, were granular, spherical, yellowish-brown and demersal, with a mean diameter of 300 ± 14.5μm. The formation of the first polar body occurred about 1 hr 20 mins after fertilization at the water temperature of 27.4 ℃. The 2-cell stage occurred at 2 hrs 10 mins, and the 4-cell stage occurred at 3 hrs 35 mins. At 9 hrs 10 mins, 8-cell stage formed, then blastula stage at 24 hrs, gastrula stage at 29 hrs. Prototrochal cilia appeared at 54 hrs and the trochophore stage developed at 70 hrs. Vesicle appeared at 80 hrs, black eye-spot and proleg cilia appeared at 89 hrs. Heartbeat began at 105 hrs, the first antenna appeared at 142 hrs, and larvae hatched out from the capsules as veliger stage at 144 hrs 10 mins.