Our projects focused on micro and macro algae culture and their effect as diets to enhance the survival and growth of postlarval and juvenile small abalone Haliotis diversicolor. The small abalone postlarvae were fed initially with two smaller, then fed the biggest diatom before and detached from the plastic plate. Afterward, sporelings of Ulva and regenerating fragments of Gracilaria were provided. Using the feed regimes described above five batches of 2cm juveniles were produced, the highest survival reached 8.7% at 182 days post hatch and the significantly different survival was found among these five adult groups. After the lower salinity (25 ppt) seawater continued for 3 months due to rain, though the maturation, fertilization, embryo development performed normally and had the high hatch rate, most of postlarvae without the shell. Application as diet for small abalone in 23 weeks feeding trial showed the mix diet of Gracilaria and Ulva having the highest weight gain, maturation rate (95%), survival of adult (99%) and postlarvae; the Ulva diet intermediate except the worst adult survival (80%) and maturation rate (84%), the Gracilaria diet the worst in the highest FCR (51) than the Ulva (21).