The mortality of post-larval small abalone occurred in 9-22 days after settlement on theplastic plates and have resulted in low survival less than 1% since 2001. The settlementof abalone larvae in response to diatom films depends on abalone species, diatom speciesand density of diatom. Traditionally using the natural diatom films could somewhatcontrol the quantity, but hardly for the quality. This study aims for isolating the suitablediatoms for post-larval small abalone, and research on their identification, collectionculture and growth characteristics. Finally, technique for control and management ofdiatom films on settlement plates could be developed and the most critical problems inabalone aquaculture could be resolved.