The objective of this research was to obtain net mesh bottom wall construction of “jodang” trap that selective to babylon tiger snails size, i.e. only shell length of l < 4.27 cm approximately could pass through. There were 3 designs shapes of bottom wall construction tested, i.e. rectangular shape of 2.4 ´ 2.8 (cm) and 2 diamond shapes with net mesh size of 5,6 cm and primary hanging ratio of E1 = 0.7 and 0.5. The results showed that rectangular shape bottom wall trap construction was better than those two other constructions. Only 6.78% of snails with l ³ 4.27 cm could escape the rectangular shape bottom wall trap construction. Whereas 41.90% and 17.46% of snail shells with l ³ 4.27 cm could escape from both the diamond mesh bottom wall trap construction. According to selectivity curve, the rectangular shape bottom wall trap construction could retained snails with shells length of l ³ 4.33 cm. The two others retained shells length of l ³ 4.14 cm and l ³ 4.60 cm.